Ethylene-a-olefin copolymer and olefin resin composition

ABSTRACT

[Problem] To provide an ethylene-α-olefin copolymer that is highly effective in improving the molding properties of polyolefin resins and at the same time highly effective improving the balance between impact strength and stiffness. 
     [Solution] Provided is an ethylene-α-olefin copolymer having a specific MFR, a specific density, and a specific molecular weight distribution, containing a suitable amount of a long-chain branching structure characterized by a branching index, and having a specific composition distribution structure characterized by solvent fractionation behavior.

TECHNICAL FIELD

The present invention relates to a novel ethylene-α-olefin copolymer anda novel olefin resin composition. More specifically, the presentinvention relates to an ethylene-α-olefin copolymer that is for use inmodifying polyolefin resins and has a high ability to improve themoldability of a polyolefin resin and to adequately improve the balancebetween the impact strength and stiffness of the resin when blended withthe resin, and the present invention also relates to an olefin resincomposition containing such an ethylene-α-olefin copolymer.

BACKGROUND ART

In recent years, plastic films, sheets, injection-molded products,pipes, extrusion-molded products, and blow-molded products areincreasingly used in various industrial fields. In particular,polyolefin resins (olefin polymers) are widely used because of low costand light weight, a high level of moldability, stiffness, impactstrength, transparency, chemical resistance, and recyclability, andother reasons. In general, polyolefin resins are subjected to moldingwhile kept in a melted state. In many cases, however, olefinhomopolymers have insufficient melt properties such as insufficientfluidity and elongational viscosity, have difficulty in maintainingsufficient moldability, or have an insufficient level of solid stateproperties such as transparency and stiffness.

Among polyethylene resins, linear low density polyethylene (L-LDPE)obtained by catalytic polymerization of ethylene and α-olefin is knownas a high-strength resin. However, it is difficult to provide reliablemoldability for L-LDPE alone, and L-LDPE has disadvantages such as lowtransparency and stiffness. As a measure to compensate for thesedisadvantages, high-pressure process low-density polyethylene (HPLD)with high moldability or an olefin polymer as a modifier with adifferent molecular weight or a different density has been blended toimprove the melt properties or the solid state properties.

Unfortunately, the use of HPLD as a modifier can cause a problem such asa reduction in impact strength although it can improve moldability, andthe use of an olefin polymer with a different molecular weight ordensity can cause a problem such as insufficient moldability ordegradation of transparency due to a widened distribution of molecularweight or copolymer composition.

The current enforcement of the Law for the Promotion of SortedCollection and Recycling of Containers and Packages and the currenttrend toward resource conservation require a reduction in theconsumption of raw material resins. From this point of view, there is anincreasing demand for a reduction in the thickness of molded products.This demand requires an improvement of impact strength and stiffness(elastic modulus).

Reduction of the density of ethylene polymers is a well-known method forimproving impact strength. However, this method can also reduce thestiffness (or make the polymers soft) and thus is not preferred.Attempts for the thickness reduction include, for example, the use of acombination of two specific ethylene-α-olefin copolymers with differentdensities and the use of a three-component blend composition containinga specific HPLD for improving moldability and transparency (see PatentLiterature 1).

These methods can produce polyethylene resin compositions with hightransparency and a good balance between impact strength and stiffness ascompared with those of traditional compositions. In these methods,however, a reduction in impact strength is inevitably associated withthe HPLD blending, and the blending of three ethylene polymers isconsidered to be economically disadvantageous in terms of stable supplyof constant-quality products at an industrial level as compared withtransitional methods.

In recent years, it has been reported that polyolefin resin-modifyingethylene polymers for improving moldability and resin strength at thesame time are developed by utilizing a polymerization designingtechnique with a metallocene catalyst that allows a long-chain branchingstructure to be formed in ethylene polymers. Examples of such atechnique include a technique in which an ethylene polymer containinglong-chain branches exhibiting specific elongational viscosity behavioris used as a modifier and blended with the target polyolefin resin (seePatent Literature 2), a technique in which a low-densityethylene-propylene copolymer having a long-chain branching structuredefined by a specific polymer molecular structure index and a specificintrinsic viscosity ratio is used as a modifier to form a resincomposition (see Patent Literature 3), and a technique in whichlong-chain branching polyethylene with a wide molecular weightdistribution exhibiting high flow activation energy is used as amodifier (see Patent Literature 4). These techniques can prevent asignificant reduction in the impact strength of polyolefin resins, whichwould otherwise be caused by traditional modification with HPLD, but arestill not able to prevent a reduction in strength or transparency andstill at an insufficient improvement level because of insufficientdesign of the long chain branching ethylene polymer.

Under these circumstances, there has been continued development of amodifying ethylene polymer that can solve the problems with conventionalmodifying ethylene polymers and provide high moldability, a good balancebetween impact strength and stiffness, and high transparency, and therehave been continued studies on a metallocene polymerization catalystthat is useful for the development of an ethylene polymer with suchproperties and capable of controlling a long-chain branching structure(see Patent Literatures 5 to 8). Among them, a transition metal catalystcomprising a specific cyclopentadienyl compound, which has been recentlyfound by the inventor et al., is proposed as a highly active catalystfor ethylene-u-olefin copolymers with preferred long-chain branching(Patent Literature 8).

CITATION LIST Patent Literatures

Patent Literature 1: JP 2010-031270 A

Patent Literature 2: JP 2012-214781 A

Patent Literature 3: JP 09-031260 A.

Patent Literature 4: JP 2007-119716 A

Patent Literature 5: JP 2004-217924 A

Patent Literature 6: JP 2004-292772 A

Patent Literature 7: JP 2005-206777 A

Patent Literature 8: JP 2013-227271 A.

SUMMARY OF INVENTION Technical Problem

In view of the above problems with the conventional art, an object ofthe present invention is to provide an ethylene-α-olefin copolymer thatis highly effective in improving the molding properties of polyolefinresins and at the same time highly effective in adequately improving thebalance between impact strength and stiffness, and to provide an olefinresin composition containing such an ethylene-α-olefin copolymer.

Solution to Problem

As a result of intensive studies to achieve the object, the inventorshave accomplished the present invention based on the finding that anethylene-α-olefin copolymer having a specific long-chain branchingindex, a relatively narrow reverse comonomer composition distributionindex, a specific MFR, and a specific density is highly effective,particularly as resin-modifying polyethylene, in improving the balancebetween impact strength and stiffness. The inventors also have foundthat controlled polymerization under specific conditions using aspecific catalyst developed by the applicant recently makes it possibleto efficiently obtain the ethylene-α-olefin copolymer having a desiredlevel of long-chain branching index and composition distribution index.

Specifically, a first aspect of the present invention provides anethylene-α-olefin copolymer satisfying the following conditions (1),(2), (5), (7), and (9):

(1) the copolymer has a MFR of more than 0.1 g/10 minutes but riot morethan 10 g/10 minutes;

(2) the copolymer has a density of 0.895 to 0.940 g/cm³;

(5) the copolymer has a minimum branching index (gc) of 0.40 to 0.85 asmeasured for branching index g′ in the molecular weight range of 100,000to 1,000,000 width a GPC measurement system comprising a combination ofa differential refractometer, a viscosity detector, and a lightscattering detector;

(7) the copolymer has a sum (W₂+W₃) of a content (W₂) and a content (W₃)of more than 40% by weight but less than 56% by weight, wherein W₂ is acontent of components with molecular weights equal to or more than aweight average molecular weight in components eluted at temperaturesequal to or lower than a temperature where an eluted amount determinedfrom an integral elution curve measured by cross fractionationchromatography (CFC) is 50 wt %, and W₃ is a content of components withmolecular weights less than the weight average molecular weight incomponents eluted at temperatures higher than the temperature where theeluted amount determined from the integral elution curve, is 50 wt %;and

(9) a difference (W₂−W₄) between W₂ and W₄ is more than 0% by weight butless than 20% by weight.

A. second aspect of the present invention provides an ethylene-α-olefincopolymer according to the first aspect of the present invention andfurther satisfying the following condition. (1′):

(1′) the copolymer has a MFR of more than 0.1 g/10 minutes but not morethan 1.0 g/10 minutes.

A third aspect of the present invention provides an ethylene-α-olefincopolymer according to the first or second aspect of the presentinvention and further satisfying the following condition (2′):

(2′) the copolymer has a density of not less than 0.898 g/cm³ but lessthan 0.934 g/cm³.

A fourth aspect of the present invention provides an ethylene-α-olefincopolymer according to any one of the first to third aspects of thepresent invention in which the α-olefin has three to ten carbon atoms.

A fifth aspect of the present invention provides an ethylene-α-olefincopolymer according to any one of the first to fourth aspects of thepresent invention and further satisfying the following condition (3):

(3) the copolymer has a molecular weight distribution Mw/Mn of 3.0 to5.5 as measured by gel permeation chromatography (GPC).

A sixth aspect of the present invention provides an ethylene-α-olefincopolymer according to any one of the first to fifth aspects of thepresent invention and further satisfying the following condition (4):

(4) the copolymer has a molecular weight distribution Mz/Mw of 2.0 to6.0 as measured by GPC.

A seventh aspect of the present invention provides an ethylene-α-olefincopolymer according to any one of the first to sixth aspect of thepresent invention and further satisfying the following condition (6):

(6) a content (X) of components eluted at 85° C. or higher bytemperature rising elution fractionation (TREF) is 2 to 15% by weight.

An eighth aspect of the present invention provides an ethylene-α-olefincopolymer according to any one of the first to seventh aspects of thepresent invention and further satisfying the following condition (8):

(8) the copolymer has a sum (W₂+W₄) of W₂ and W₄ of more than 25% byweight but less than 50% by weight.

A ninth aspect of the present invention provides a method for producingthe ethylene-α-olefin copolymer according to any one of the first toeighth aspects of the present invention, the method comprising producingthe ethylene-α-olefin copolymer using an olefin polymerization catalystcomprising the following components (A), (B) and (C):

(A) a bridged cyclopentadienyl indenyl compound containing a transitionmetal element;

(B) a compound capable of reacting with the compound of the component(A) to form a cationic metallocene compound; and

(C) an inorganic compound carrier.

A tenth aspect of the present invention provides a method according tothe ninth aspect of the present invention for producing theethylene-α-olefin copolymer, wherein the ratio of number of moles of ametal in the component (B) to 1 g of the component (C) is more than0.006 (moles/g) to 0.020 (moles/g).

An eleventh aspect of the present invention provides a method forproducing the ethylene-α-olefin copolymer according to any one of thefirst to eighth aspects of the present invention, the method comprisingcopolymerizing ethylene and an α-olefin by a gas phase method or aslurry method.

A twelfth aspect of the present invention provides an olefin resincomposition comprising: the ethylene-α-olefin copolymer according to anyone of the first to eighth aspects of the present invention; and one ormore other olefin resins.

A thirteenth aspect of the present invention provides an olefin resincomposition according to the twelfth aspect of the present invention,wherein an amount of the ethylene-α-olefin copolymer contained in theresin composition is 1 to 59% by weight.

A fourteenth aspect of the present invention provides an olefin resincomposition according to the twelfth or thirteenth aspect of the presentinvention which comprises an additional ethylene-α-olefin copolymer (B)other than the copolymer (A) as an olefin resin other than the copolymer(A).

A fifteenth aspect of the present invention provides an olefin resincomposition according to the fourteenth aspect of the present invention,wherein the additional ethylene-α-olefin copolymer (B) satisfies thefollowing conditions (B-1) and (B-2):

(B-1) the copolymer (B) has a MFR of 0.01 to 20 g/10 minutes; and

(B-2) the copolymer (B) has a density of 0.880 to 0.970 g/cm³.

A sixteenth aspect of the present invention provides an olefin resincomposition according to the fifteenth aspect of the present invention,wherein the additional ethylene-α-olefin copolymer (B) further satisfiesthe following condition (B-3):

(B-3) the copolymer (B) has a molecular weight distribution Mw/Mn of 2.0to 4.0 as measured by gel permeation chromatography (GPC).

An seventeenth aspect of the present invention provides an olefin resincomposition according to any one of the twelfth to sixteenth aspects ofthe present invention, wherein the ethylene-α-olefin copolymer (A) andthe ethylene-olefin copolymer (B) satisfy at least one of the followingconditions

(AB-1) MFR_(B)>MFR_(A); and

(AB-2) [Mw/Mn]_(B)<[Mw/Mn]_(A),

wherein MFR_(A) represents MFR of the ethylene-α-olefin copolymer (A),[Mw/Mn]_(A) represents the molecular weight distribution MW/Mn of theethylene-α-olefin copolymer (A) measured by gel permeationchromatography (GPC), MFR_(B) represents MFR of the ethylene-α-olefincopolymer (B), and [Mw/Mn]_(B) represents the molecular weightdistribution Mw/Mn of the ethylene-α-olefin copolymer (B) measured bygel permeation chromatography (GPC).

An eighteenth aspect of the present invention provides an olefin resincomposition according to any one of the twelfth to seventeenth aspectsof the present invention, wherein the ethylene-α-olefin copolymer (B) isa linear low density polyethylene having a MFR of not less than 0.1 toless than 5.0 and produced with a Ziegler catalyst or metallocenepolyethylene having a MFR of 0.1 to 10 and produced with a metallocenecatalyst.

A nineteenth aspect of the present invention provides film obtained fromthe ethylene-α-copolymer according to any one of the first to eighthaspects of the present invention or the resin composition according toany one of the twelfth to eighteenth aspects of the present invention.

Advantageous Effects of Invention

The ethylene-α-olefin copolymer of the present invention is highlyeffective, as a modifier for polyolefin resins, in improving moldingproperties and at the same time highly effective in adequately improvingthe balance between impact strength and stiffness. The polyolefin resinmodified with the ethylene-α-olefin copolymer of the present inventionis expected to allow constant-quality products with a good balancebetween impact strength and stiffness to be supplied stably at anindustrial level.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a graph showing a base line and an interval with respect to achromatogram for use in gel permeation chromatography (GPC).

FIG. 2 is a graph showing a molecular weight distribution curvecalculated from GPC-VIS measurement (branching structure analysis) andthe relationship between branching index (g′) and molecular weight (M).

FIG. 3 is a graph showing an elution temperature distribution obtainedby temperature rising elution fractionation (TREF).

FIG. 4 is a graph showing, as a contour map, eluted amounts with respectto elution temperature and molecular weight measured by crossfractionation chromatography (CFC).

FIG. 5 is a graph showing the relationship between elution temperatureand elution content (wt %) at each elution temperature measured by crossfractionation chromatography (CFC).

FIG. 6 is a graph showing the relationship between the elastic modulusand impact strength of films produced using bends with the copolymers ofexamples according to the present invention and blends with thecopolymers of comparative examples, respectively.

FIG. 7 is a schematic diagram about W₁ to W₄. In the drawing, theabscissa axis represents the logarithm (log M) of molecular weight whilethe abscissa axis represents elution temperature (Temp.).

DESCRIPTION OF EMBODIMENTS

The present invention is directed to an ethylene-α-olefin copolymerhaving a specific long-chain branching index, a relatively narrowreverse comonomer composition distribution index, a specific MFR, and aspecific density and being suitable as a modifier for polyolefin resin.Hereinafter, the ethylene-α-olefin copolymer of the present invention,specifically conditions (1) to (9) featuring the ethylene-α-olefincopolymer, and the method for producing the ethylene-α-olefin copolymer(specifically, each component of a polymerization catalyst for use inthe production method, the method for preparing the catalyst, and thepolymerization method) will be described in detail item by item.

1. Ethylene-α-olefin Copolymer of the Present Invention.

The ethylene-α-olefin copolymer of the present invention satisfies allof conditions (1), (2), (5), (7), and (9) described below. Specifically,the ethylene-α-olefin copolymer of the present invention has a newfeature in that it has a specific level of MFR and density (conditions 1and 2), long-chain branching in a suitable range (condition 5), and arelatively narrow reverse comonomer composition distribution with anappropriate content of low-density, high-molecular-weight components(conditions 7 and 9).

Many conventional ethylene-α-olefin copolymers usually obtained bycatalytic polymerization have what is called a normal comonomercomposition distribution (reverse comonomer composition distribution).Although there have been some reports showing that ethylene-α-olefincopolymers with what is called a reverse comonomer compositiondistribution are obtained using a certain catalytic species, most ofsuch copolymers have no long-chain branching structure. According to thepresent invention, the ethylene-α-olefin copolymer having a suitabledegree of long-chain branching structure and a relatively narrow reversecomonomer composition distribution with a suitable content oflow-density, high-molecular-weight components is highly effectiveparticularly in improving molding properties and at the same time highlyeffective in improving the balance between impact strength andstiffness. Such advantageous effects have not been found before. Thepresent invention is also based on the finding that theethylene-α-olefin copolymer with such features can be advantageouslyproduced using a specific catalyst species developed recently, which isillustrated later in the section about the method for producing theethylene-α-olefin copolymer of the present invention.

1-1. Condition (1)

The ethylene-α-olefin copolymer of the present invention has a melt flowrate (MFR) of more than 0.1 g/10 minutes but not more than 10 g/10minutes, preferably more than 0.1 g/10 minutes but not more than 1.0g/10 minutes, more preferably more than 0.1 g/10 minutes but not morethan 0.5 g/10 minutes, even more preferably more than 0.1 g/10 minutesbut not more than 0.4 g/10 minutes.

The ethylene-α-olefin copolymer with a MFR in this range is highlyeffective in improving moldability and the balance between impactstrength and stiffness when blended with polyolefin resins. On the otherhand, an ethylene-α-olefin copolymer with a MFR of 0.1 g/10 minutes orless is not preferred in view of moldability and other properties insome cases, and an ethylene-α-olefin copolymer with a MFR of more than10 g/10 minutes is less likely to be sufficiently effective in improvingimpact strength or stiffness and thus is not preferred. In the presentinvention, the MFR of the ethylene-α-olefin copolymer refers to thevalue measured under the conditions of 190° C. and a load of 21.18 N(2.16 kg) according to “Plastics—Testing method for the melt mass-flowrate (MFR) and melt volume-flow rate (MVR) of thermoplastics” in JIS K7210.

1-2. Condition (2)

The ethylene-α-olefin copolymer of the present invention has a densityof 0.895 g/cm³ to 0.940 g/cm³, preferably 0.898 or more and less than0.934 g/cm³, more preferably 0.900 to 0.930 g/cm³, even more preferably0.910 to 0.930 g/cm³, further more preferably 0.915 to 0.925 g/cm³.

The ethylene-α-olefin copolymer with a density in this range is highlyeffective in improving the balance between impact strength and stiffnesswhen blended with the polyolefin resin to be modified. On the otherhand, an ethylene-α-olefin copolymer with a density of less than 0.895g/cm³ is not preferred in view of stiffness in some cases, and anethylene-α-olefin copolymer with a density of more than 0.940 g/cm³ isnot sufficiently effective in improving impact strength or otherproperties and thus is not preferred.

In the present invention, the density of the ethylene-α-olefin copolymerrefers to the value measured by the method described below.

Pellets were subjected to hot pressing to form a pressed sheet with athickness of 2 mm. The sheet was placed in a 1,000-ml volume beaker,which was filled with distilled water, then covered with a watch glass,and subjected to heating with a mantle heater. After the distilled waterwas boiled for 60 minutes from the start of boiling, the beaker wasplaced on a wooden board and allowed, to cool. In this process, thevolume of the boiled distilled water after the 60-minute boiling was 500ml, and the time taken for the boiled water to cool to room temperaturewas controlled not to be 60 minutes or less. The test sheet was immersedin water almost at the center so that it was not in contact with thebeaker or the water surface. The sheet was annealed for 16 to 24 hoursunder the conditions of 23° C. and a humidity of 50% and then stampedinto 2 mm long, 2 mm wide pieces, which were subjected to measurement ata test temperature of 23° C. according to “Plastics—Methods ofdetermining the density and specific gravity of non-cellular plastics”in JIS K 7112.

1-3. Condition (5)

In addition to conditions (1) and (2) above, the ethylene-α-olefincopolymer of the present invention has a minimum branching index (gc) of0.40 to 0.85, preferably 0.45 to 0.85 or 0.50 to 0.85, more preferably0.50 to 0.77, even more preferably 0.51 to 0.75 as measured forbranching index gc in the molecular weight range of 100,000 to 1,000,000with a GPC measurement system comprising a combination of a differentialrefractometer, a viscosity detector, and a light scattering detector. Anethylene-α-olefin copolymer with a g_(c) value of more than 0.85 is notpreferred because it is not sufficiently effective in improvingmoldability when blended with polyolefin resins. An ethylene-α-olefincopolymer with a g_(c) value of less 0.40 is not preferred because itcan reduce the impact strength or transparency of polyolefin resinsalthough it can improve the moldability the polyolefin resins.

In the present invention, the g_(c) value of the ethylene-α-olefincopolymer is a physical property value indicating the degree of growthof long-chain branches introduced into the copolymer. A greater g_(c)value indicates a smaller amount of long-chain branches, and a smallerg_(c) value indicates a larger amount of introduced long-chain branches.The g_(c) value can be generally controlled by selecting the catalystused for the polymerization. The g_(c) value of the ethylene-α-olefincopolymer is a measure for evaluating the amount of long-chain branchesusing the branching index (g′) and the molecular weight distributioncurve calculated from the GPC-VIS measurement described below.

[Analysis of Branching Structure by GPC-VIS]

Alliance GPCV 2000 from Waters was used as a GPC system equipped with adifferential refractometer (RT) and a viscosity detector (viscometer). Amultiangle laser light scattering detector (MALLS) DAWN-E from WyattTechnology was used as a light scattering detector. The detectors wereconnected in the following order: MALLS, RI, and Viscometer. The mobilephase solvent was 1,2,4-trichlorobenzene (to which an antioxidantIrganox 1076 was added at a concentration of 0.5 mg/mL). The flow ratewas 1 mL/minute. Two GMHHR-H (S) HT columns from Tosoh Corporation wereconnected and used.

The temperature of the columns, the sample injection port, and eachdetector was 140° C. The sample concentration was 1 mg/mL. The injectionvolume (sample loop volume) was 0.2175 mL. The absolute molecular weight(M) and the square radius of gyration (Rg), which were obtained from theMALLS, and the intrinsic viscosity ([η]), which was obtained from theviscometer, were calculated with reference to the literatures belowusing data processing software ASTRA (version 4.73.04) included with theMALLS.

Reference Literatures:

1. Developments in polymer characterization, vol.4. Essex: AppliedScience; 1984. Chapter 1.

2. Polymer, 45, 6495-6505 (2004)

3. Macromolecules, 33, 2424-2436 (2000)

4. Macromolecules, 33, 6945-6952 (2000)

[Calculation of Branching Index (g_(c)) and Other Values]

The branching index (g′) is calculated as the ratio (ηbranch/ηlin) ofthe intrinsic viscosity (ηbranch) obtained by measuring the sample withthe viscometer to the intrinsic viscosity (ηlin) obtained by measuring alinear polymer separately.

A polymer molecule with introduced long-chain branches has a radius ofgyration smaller than that of a linear polymer molecule of the samemolecular weight. The intrinsic viscosity decreases with decreasingradius of gyration. Therefore, as long-chain branches are introduced,the ratio (ηbranch/ηlin) of the intrinsic viscosity (ηbranch) of thebranched polymer to the intrinsic viscosity (ηlin) of a linear polymerof the same molecular weight decreases. Therefore, a branching index(q′=ηbranch/ηlin) of less than 1 means that the polymer has introducedbranches, and a smaller branching index means a larger amount ofintroduced long-chain branches. Specifically, in the present invention,the minimum g′ value in the molecular weight range of 100,000 to1,000,000 with respect to the absolute molecular weight obtained fromthe MALLS is calculated as the g_(c) value. FIG. 2 shows exemplaryresults of the GPC-VIS analysis. The molecular weight distribution curvedetermined based on the molecular weight (M) obtained from the MALLS andthe concentration obtained from the RI is shown on the left of FIG. 2,while the branching index (g′) at the molecular weight (M) is shown onthe right of FIG. 2. In this case, Linear Polyethylene StandardReference Material 1475a (National Institute of Standards & Technology)was used as the linear polymer.

1-4. Condition (7)

In addition to conditions (1), (2), and (5) above, the ethylene-α-olefincopolymer of the present invention has a sum (W₂+W₃) of a content (W₂)and a content (W₃) of more than 40% by weight but less than 56% byweight, wherein W₂ is a content of components with molecular weightsequal to or more than the weight average molecular weight in thecomponents eluted at temperatures equal to or lower than the temperaturewhere the eluted amount determined from the integral elution curvemeasured by cross fractionation chromatography (CFC) is 50 wt % and W₃is a content of components with molecular weights less than the weightaverage molecular weight in the components eluted at temperatures higherthan the temperature where the eluted amount determined from theintegral elution curve is 50 wt %. The sum (W₂+W₃) is preferably morethan 41% by weight but less than 56% by weight, more preferably morethan 43% by weight to less than 56% by weight, even more preferably morethan 45% by weight but less than 56% by weight.

The values W₁ and so on obtained from the integral elution curvemeasured by cross fractionation chromatography (CFC) are measures usedto indicate the “comonomer composition distribution,” which indicatesthe distribution of all the comonomer amounts and molecular weights ofindividual polymers in the whole copolymer. Specifically, the valuesindicate the content (W₁) of polymers with a relatively large amount ofthe comonomer and with relatively low molecular weights, the content(W₂) of polymers with a relatively large amount of the comonomer andwith relatively high molecular weights, the content (W₃) of polymerswith a relatively small amount of the comonomer and with relatively lowmolecular weights, and the content (W₄) of polymers with a relativelysmall amount of the comonomer and with relatively high molecularweights, in the whole copolymer. FIG. 7 is a schematic diagram showingW₁ to W₄.

Conventional ethylene-α-olefin copolymers obtained by common catalyticpolymerization have what is called a normal comonomer composition, inwhich specifically, W₁+W₄ is often at least 60% by weight and W₂+W₃ isoften at most 40% by weight. In contrast, one of the features of theethylene-α-olefin copolymer obtained as a preferred example of thepresent invention using the specific catalyst shown in Example 1 hereinis that the copolymer has what is called a reverse comonomercomposition, in which specifically, W₂+W₃ is more than 40% by weight butless than 56% by weight.

If the W₂+W₃ value is 40% by weight or less, the ethylene-α-olefincopolymer can have a reduced content of low-density,high-molecular-weight components, which effectively act to improve theimpact strength of polyolefin resins, or have a reduced content ofhigh-density, low-density components, which effectively act to improvethe stiffness of polyolefin resins, so that a larger amount of theethylene-α-olefin copolymer will need to be blended in order to producethe physical property-improving effect, which is not economical and thusnot preferred. On the other hand, if the W₂+W₃ value is 56% by weight ormore, the contents of the high-density, low-molecular-weight componentsand the low-density, high-molecular-weight components in theethylene-α-olefin copolymer can be unbalanced, so that the effect ofimproving the physical properties of polyolefin resins will not beproduced as expected or the high-density, low-molecular-weightcomponents and the low-density, high-molecular-weight components canhave poor dispersibility, which can cause degradation of transparency orgelation and thus is not preferred.

[CFC Measurement Conditions]

A cross fractionation chromatograph (CFC) includes a temperature risingelution fractionation (TREF) part, in which crystallizabilityfractionation is performed, and a gel permeation chromatography (GPC)part, in which molecular weight fractionation is performed.

The analysis using the CFC may be performed as follows.

First, a polymer sample is completely dissolved at 140° C. ino-dichlorobenzene (ODCB) containing 0.5 mg/mL of BHT. The samplesolution is then injected through the sample loop of the chromatographinto its TREF column (a column packed inactive glass bead carriers) heldat 140° C. The solution is gradually, cooled to a predetermined firstelution temperature so that the polymer sample is crystallized. Afterthe sample is held at the predetermined temperature for 30 minutes, ODCBis allowed to pass through the TREF column so that he eluted componentis injected into the GPC part to undergo molecular weight fractionation,in which a chromatogram is obtained with an infrared detector (MIRAN 1AIR Detector manufactured by FOXBORO, measurement wavelength 3.42 μm).During this process, the temperature of the TREF part is raised to thenext elution temperature, so that the component eluted at a secondelution temperature is injected into the GPC part after the chromatogramat the first elution temperature is obtained. Thereafter, the sameoperation repeated to obtain the chromatogram of the component eluted ateach elution temperature.

The CFC measurement conditions are as follows.

Chromatograph: CFC-T102 L manufactured by Dia Instruments Co., Ltd.

GPC columns: AD-806MS (three columns connected in series) manufacturedby Showa Denko K.K.

Solvent: ODCB

Sample concentration: 3 mg/mL

Injection volume: 0.4 mL

Crystallization rate: 1° C./minute

Solvent flow rate: 1 mL/minute

GPC measurement time: 34 minutes

Stabilization time after GPC measurement: 5 minutes

Elution temperatures: 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 49, 52, 55,58, 61, 64, 67, 70, 73, 76, 79, 82, 85, 88, 91, 94, 97, 100, 102, 120,140

[Data Analysis]

The chromatogram (obtained by the measurement) of the components elutedat the respective elution temperatures is used to calculate thenormalized eluted amounts (proportional to the areas in thechromatogram), the sum of which is 100%.

An integral elution curve against elution temperature is furthercalculated as shown in FIG. 5. The integral elution curve is thendifferentiated by temperature to calculate a differential elution curve.

The molecular weight distribution is also calculated from the respectivechromatograms by the procedure described below. The retention volume isconverted to the molecular weight using a calibration curve prepared inadvance with polystyrene standards. All the polystyrene standards usedare the following products manufactured by Tosoh Corporation. F380,F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000.

The calibration curve is prepared using a solution of 0.3 mg/mL of eachstandard in ODCB (containing 0.5 mg/mL of BHT), which is injected in avolume of 0.4 mL.

A cubic equation obtained by least squares approximation is used for thecalibration curve.

The conversion to the molecular weight is performed using ageneral-purpose calibration curve with reference to Sadao Mori, “SizeHaijo Chromatography” (Size Exclusion Chromatography), Kyoritsu ShuppanCo., Ltd. In this process, the following values are used in theviscosity formula [η] K×W^(α).

PS: K=1.38×10⁻⁴, α=0.7

PE: K=3.92×10⁻⁴, α=0.733

In some cases, the peak of BHT added to the solvent overlaps with thelow-molecular-weight side of the peak of the eluted component in thechromatogram at the first elution temperature. In such cases, a baseline is drawn as shown in FIG. 1 to define the interval in which themolecular weight distribution is to be determined.

In addition, as shown in Table 1 below, the whole weight averagemolecular weight is calculated from the elution contents (wt % in thetable) and the weight average molecular weights (Mw in the table) at therespective elution temperatures.

TABLE 1 Example of commercially available high-pressure radical processlow-density polyethylene Elution temperature wt % Mn Mw Mz Mw/Mn Mz/Mw 00.59 759 927 1,128 1.22 1.22 5 0.04 661 863 1,104 1.31 1.28 10 0.101,131 1,392 1,642 1.23 1.18 15 0.25 791 1,613 2,412 2.04 1.50 20 0.151,654 1,904 2,218 1.15 1.16 25 0.21 1,838 2,493 3,157 1.36 1.27 30 0.281,114 1,893 2,703 1.70 1.43 35 0.49 2,446 3,240 4,163 1.32 1.28 40 1.122,581 4,494 7,000 1.74 1.56 45 0.89 3,479 4,420 5,459 1.27 1.24 49 1.153,220 4,887 6,339 1.52 1.30 52 1.13 4,718 6,625 8,685 1.40 1.31 55 1.504,282 8,263 13,172 1.93 1.59 58 2.03 5,050 9,954 14,794 1.97 1.49 613.06 5,346 13,966 21,229 2.61 1.52 64 3.32 9,081 17,509 25,958 1.93 1.4867 5.19 11,776 27,561 46,764 2.34 1.70 70 6.42 16,910 46,894 94,126 2.772.01 73 11.75 16,214 80,906 221,026 4.99 2.73 76 26.15 15,456 137,503326,112 8.90 2.37 79 30.48 16,126 134,046 316,574 8.31 2.36 82 3.5430,949 118,833 370,535 3.84 3.12 85 0.16 47,228 54,637 61,765 1.16 1.1388 0.00 0 0 0 0.00 0.00 91 0.00 0 0 0 0.00 0.00 94 0.00 0 0 0 0.00 0.0097 0.00 0 0 0 0.00 0.00 100 0.00 0 0 0 0.00 0.00 102 0.00 0 0 0 0.000.00 120 0.00 0 0 0 0.00 0.00 140 0.00 0 0 0 0.00 0.00 0 0.00 0 0 0 0.000.00 0 0.00 0 0 0 0.00 0.00 0 0.00 0 0 0 0.00 0.00 0 0.00 0 0 0 0.000.00 whole 10,016 96,554 297,081 9.64 3.08

In addition, a graph (contour map) showing, as contour lines, the elutedamounts with respect to elution temperature and molecular weight isobtained as shown in FIG. 4 from the eluted amounts and the molecularweight distributions at the respective elution temperatures according tothe method described in the literature: S. Nakano, Y. Goto, “Developmentof Automatic Cross Fractionation: Combination of CrystallizabilityFractionation and Molecular Weight Fractionation,” J. Appl. Polym. Sci.,vol. 26, pp. 4217-4231 (1981).

Using the contour map, the following contents are determined.

W₁: the content of components with molecular weights less than theweight average molecular weight in the components eluted at temperaturesequal to or lower than the temperature where the eluted amountdetermined from the integral elution curve is 50 wt %

W₂: the content of components with molecular weights equal to or morethan the weight average molecular weight in the components eluted attemperatures equal to or lower than the temperature where the elutedamount determined from the integral elution curve is 50 wt %

W₃: the content of components with molecular weights less than theweight average molecular weight in the components eluted at temperatureshigher than the temperature where the eluted amount determined from theintegral elution curve is 50 wt %

W₄: the content of components with molecular weights equal to or morethan the weight average molecular weight in the components eluted attemperatures higher than the temperature where the eluted amountdetermined from the integral elution curve is 50 wt %

In this case, W₁+W₂+W₃+W₄=100.

1-5. Condition (9)

In addition to conditions (1), (2), (5), and (7) described above, theethylene-α-olefin copolymer of the present invention has a difference(W₂−W₄) between W₂ and W₄ of more than 0% by weight but less than 20% byweight, preferably more than 0% by weight but less than 15% by weight,more preferably more than 1% by weight but less than 15% by weight, evenmore preferably more than 2% by weight but less than 14% by weight,further more preferably more than 2% by weight but less than 13% byweight, wherein W₂ and W₄ have the same meanings as defined above forcondition (7). An ethylene-α-olefin copolymer with a difference (W₂−W₄)of 0% by weight or less is not preferred because it can have a reducedcontent of low-density, high-molecular-weight components capable ofeffectively acting to improve the impact strength of polyolefin resins.On the other hand, if the value (W₂−W₄) is 20% by weight or more, thecontents of high-density, high-molecular-weight components andlow-density, high-molecular-weight components in the ethylene-α-olefincopolymer can be unbalanced, so that the effect of improving thephysical properties of polyolefin resins will not be produced asexpected or the ethylene-α-olefin copolymer can have poor dispersibilityin polyolefin resins, which can cause degradation of transparency orgelation and thus is not preferred.

The ethylene-α-olefin copolymer of the present invention satisfiesconditions (1), (2), (5), (7), and (9) described above as essentialconditions. In a preferred mode, the ethylene-α-olefin copolymer of thepresent invention may further satisfy at least one of conditions (3),(4), (6), and (8) described below.

1-6. Condition (3)

The ethylene-α-olefin copolymer of the present invention may have aratio (Mw/Mn) of weight average molecular weight (Mw) to number averagemolecular weight (Mn) of 3.0 to 5.5, preferably 3.0 to 5.3, morepreferably not less than 3.0 but less than 5.1, even more preferably notless than 3.2 but less than 5.1, further more preferably 3.3 to 5.0. Anethylene-α-olefin copolymer with a Mw/Mn of less than 3.0 can providelow moldability, specifically, low melt flowability and be difficult tomix with other polymer components when blended with polyolefin resins.Therefore, such a Mw/Mn ratio should be avoided. An ethylene-α-olefincopolymer with a Mw/Mn of more than 5.5 can be insufficiently effectivein improving the stiffness or impact strength of the polyolefin resin orthe molded product thereof, have degraded transparency, or tend to besticky. Therefore, such a Mw/Mn ratio is not preferred.

The Mw/Mn is an index indicating the molecular weight distribution inthe copolymer. The ratio is low when the polymerization reaction on thecatalyst is allowed to proceed at a relatively uniform site, whereas theratio is high when the reaction is allowed to proceed at relativelymultiple sites. In general, the ratio can be appropriately controlled byselecting the catalytic species used for the polymerization and thecatalyst preparation conditions.

In the present invention, the Mw and Mn of the ethylene-α-olefincopolymer refer to the values measured by gel permeation chromatography(GPC).

The retention volume is converted to the molecular weight using acalibration curve prepared in advance with polystyrene standards. Allthe polystyrene standards used are the following products manufacturedby Tosoh Corporation.

F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000.

The calibration curve, is prepared using a solution of 0.5 mg/mL of eachstandard in ODCB (containing 0.5 mg/mL of BHT), which is injected in avolume of 0.2 mL. A cubic equation obtained by least squaresapproximation is used for the calibration curve. The conversion to themolecular weight is performed using a general-purpose calibration curvewith reference to Sadao Mori, “Size Haijo Chromatography” (SizeExclusion Chromatography), Kyoritsu Shuppan Co., Ltd. In this process,the following values are used in the viscosity formula [η]=K×M^(α).

PS: K=1.38×10 ⁻⁴, α=0.7

PE: K=3.92×10⁻⁴, α=0.733

The GPC measurement conditions are as follows.

System: GPC (ALC/GPC 150C) manufactured by Waters

Detector: MIRAN 1A IR Detector manufactured by FOXBORO (measurementwavelength: 3.42 μm)

Columns: AD806M/S (three columns) manufactured by Showa Denko K.K.

Mobile phase solvent: o-dichlorobenzene

Measurement temperature: 140° C.

Flow rate: 1.0 ml/minute

volume: 0.2 ml

Sample preparation: The sample is dissolved in ODCB (containing 0.5mg/mL of BHT) at 140° C. for about 1 hour to form a 1 mg/mL, solution.

The base line and the interval for the resulting chromatogram aredetermined as illustrated in FIG. 1.

1-7. Condition (4)

The ethylene-α-olefin copolymer of the present invention may have aratio (Mz/Mw) of Z weight average molecular weight (Mz) to weightaverage molecular weight (Mw) of 2.0 to 6.0, preferably 2.1 to 5.5, morepreferably 2.2 to 5.3, even more preferably more than 2.2 but less than5.0, further more preferably not less than 2.3 but less than 3.6. Anethylene-α-olefin copolymer with a Mz/Mw of less than 2.0 can providelow moldability, specifically, low melt flowability and be difficult tomix with other polymer components when blended with polyolefin resins.Therefore, such a Mz/Mw ratio should be avoided. An ethylene-α-olefincopolymer with a Mz/Mw of more than 6.0 can be insufficiently effectivein improving the stiffness or impact strength of the polyolefin resin orthe molded product thereof, have degraded transparency, or tend to besticky, so that an excess of a high-molecular-weight component can forma gel or be highly oriented during molding to reduce the strength.Therefore, such a ratio is not preferred.

The Mz/Mw is another index indicating the molecular weight distributionin the copolymer. The ratio indicates the presence or ahigh-molecular-weight component, and the ratio is high when thehigh-molecular-weight component content is high. In general, the ratiocan be appropriately controlled by selecting the catalytic species usedfor the polymerization. In the present invention, the Mz of theethylene-α-olefin copolymer refers to the value measured by the gelpermeation chromatography (GPC) described above.

1-8. Condition (6)

In the ethylene-α-olefin copolymer of the present invention, the content(X value) of components eluted at 85° C. or higher by temperature risingelution fractionation (TREF) may be 2 to 15% by weight, preferably 4 to14% by weight. The X value is more preferably 5 to 14% by weight, evenmore preferably 6 to 14% by weight. If the X value is more than 15% byweight, the ethylene-α-olefin copolymer can have a reduced content oflow-density components capable of effectively acting to improve theimpact strength of polyolefin resins, so that the improvement of theimpact strength will require blending a large amount of theethylene-α-olefin copolymer, which is not economical and thus notpreferred. In some cases, the ethylene-α-olefin copolymer with an Xvalue of less than 2% by weight is not preferred because it can have lowcompatibility with a polyolefin resin being blended or can degrade thestiffness of the polyolefin resin. The X value is a value indicating thecontent of components with relatively high molecular weights in thecopolymer. The X value can be controlled by controlling the catalystpreparation method and the polymerization conditions.

[TREF Measurement Conditions]

The sample is dissolved in o-dichlorobenzene (containing 0.5 mg/mL BHT)at 140° C. to form a solution. The solution is introduced into a TREFcolumn at 140° C. and then cooled to 100° C. at a rate of decrease of 8°C./minute. Subsequently, the solution is cooled to 40° C. at a rate ofdecrease of 4° C./minute, then cooled to −15° C. at a rate of decreaseof 1° C./minute, and then held at the temperature for 20 minutes.Subsequently, o-dichlorobenzene (containing 0.5 mg/mL BHT) as a solventis run at a flow rate of 1 mL/minute through the column. The componentsdissolved in o-dichlorobenzene in the TREF column at −15° C. are elutedfor 10 minutes, and then the column is linearly heated to 140° C. at arate of increase of 100° C./hour, when an elution curve is obtained. Inthis process, the content of the components eluted at temperatures from85° C. to 140° C. is determined as the X value (in units of wt %).

The following system is used.

(TREF Part)

TREF column: 4.3 mmφ×150 mm stainless steel column

Column packing material: 100 μm glass beads having undergone surfaceinactivation

Heating system: Aluminum heat block

Cooling system: Peltier element (cooling Peltier element with water)

Temperature distribution: ±0.5° C.

Temperature controller: Digital Program Controller KP1000 from CHINOCorporation

(Valve Oven)

Heating system: Air bath oven

Temperature during measurement: 140° C.

Temperature distribution: ±1° C.

Valves: Six-sided valve, four-sided valve

(Sample Injection Part)

Injection system: Loop injection system

Injection volume: Loop size 0.1 ml

Injection port heating system: Aluminum heat block

Temperature during measurement: 140° C.

(Detection Part)

Detector: Fixed wavelength infrared detector MIRAN 1A manufactured byFOXBORO

Detection wavelength: 3.42 μm

High-temperature flow Cell: Micro flow Cell for LC-IR, optical path 1.5mm, window shape 2φ×4 mm oval, synthetic sapphire window plate

Temperature during measurement: 140° C.

(Pump Part)

Feed pump: SSC-3461 Pump manufactured b), Senshu Scientific Co., Ltd.

Measurement Conditions

Solvent: O-dichlorobenzene (containing 0.5 mg/mL BHT)

Sample concentration: 5 mg/mL

Sample injection volume: 0.1 mL

Solvent flow: 1 mL/minute

1-9. Condition (8)

The ethylene-α-olefin copolymer of the present invention may have a sum(W₂+W₄) of W₂ and W₄ of more than 25% by weight but less than 50% byweight, preferably more than 29% by weight but less 50% by weight, morepreferably more than 29% by weight but less than 45% by weight, evenmore preferably 30 to 43% by weight, further more preferably 30 to 42%by weight, wherein W₂ and W₄ have the same meanings as defined above forcondition (7). If W₂+W₄ is 25% by weight or less, the ethylene-α-olefincopolymer can have a reduced content of high-molecular-weight componentscapable of effectively acting to improve the impact strength ofpolyolefin resins (such a reduced content is not preferred), or theethylene-α-olefin copolymer can have a reduced content ofhigh-molecular-weight, long-chain branching components capable ofeffectively acting to improve the moldability of polyolefin resins (sucha reduced content is not preferred), so that due to the reduction in thecontent of high-molecular-weight components or long-chain branchingcomponents, a larger amount of the ethylene-α-olefin copolymer will needto be blended in order to modify polyolefin resins, which can reduce thecost effectiveness.

On the other hand, if the W₂+W₄ value is 50% by weight or more, thecontent of high-molecular-weight components or high-molecular-weight,long-chain branching components in the ethylene-α-olefin copolymer canbe high so that the copolymer can have low dispersibility in apolyolefin resin to degrade transparency or form a gel, which is notpreferred.

1-9. Composition of the Ethylene-α-Olefin Copolymer of the PresentInvention

The ethylene-α-olefin copolymer of the present invention is a copolymerof ethylene and an α-olefin of 3 to 10 carbon atoms. Examples of theα-olefin for use as a copolymerizable component include propylene,butene-1, 3-methylbutene-1, 3-methylpentene-1, 4-methylpentene-1,pentene-1, hexene-1, heptene-1, octene-1, nonene-1, and decene-1. Theseα-olefins may be used singly or in combination of two or more. Inparticular, an α-olefin of 3 to 8 carbon atoms is preferred, examples ofwhich include propylene, butene-1, 3-methylbutene-1, 4-methylpentene-1,pentene-1, hexene-1, heptene-1, and octene-1. An α-olefin of 4 to 6carbon atoms is more preferred, examples of which include butene-1,4-methylpentene-1, and hexene-1. In particular, the α-olefin preferablyhexene-1.

As regards the contents or ethylene and α-olefin units, theethylene-α-olefin copolymer of the present invention may include about75 to about 99.8% by weight of the ethylene unit and about 0.2 to about25% by weight of the α-olefin unit, preferably about 80 to about 99.6%by weight of the ethylene unit and about 0.4 to about 20% by weight ofthe α-olefin unit, more preferably about 82 to about 99.2% by of theethylene unit and about 0.8 to about 18% by welg of the α-olefn unit,even more preferably about 85 to about 99% by weight of the ethyleneunit and about 1 to about 15% by weight of the α-olefin unit, furthermore preferably about 88 to about 98% by weight of the ethylene unit andabout 2 to about 12% by weight of the α-olefin unit. Theethylene-α-olefin copolymer with the ethylene unit content in this rangeis highly effective in modifying polyethylene resins.

The copolymerization may be any of alternating copolymerization, randomcopolymerization, and block copolymerization. It will be understood thata small amount of a comonomer or comonomers other than ethylene anda-olefins may also be used. In such a case, examples of the comonomerinclude styrene and styrene derivatives such as 4-methylstyrene and4-dimethylaminostyrene, diens such as 1,4-butadiene, 1,5-hexadiene,1,4-hexadiene, and 1,7-octadiene, norbornene, cyclic compounds such ascyclopentene, oxygen-containing compounds such as hexenol, hexenoicacid, and methyl octenoate, and other polymerizable doublebond-containing compounds. It will be understood that when a diene isused, the diene needs to be used in such a range that the long-chainbranching structure and the molecular weight distribution satisfyconditions (3) to (5) described above.

2. Method for Producing the Ethylene-α-Olefin Copolymer of the PresentInvention

The ethylene-α-olefin copolymer of the present invention to be usedshould be produced so as to satisfy all of conditions (1), (2), (5),(7), and (9) described above. The production is performed by a method ofcopolymerizing ethylene and the α-olefin using an olefin polymerizationcatalyst.

A preferred example of the production method capable of simultaneouslyachieving the conditions for the specific long-chain branchingstructure, compositional distribution structure, MFR, and density of theethylene-α-olefin copolymer of the present invention may be a methodusing an olefin polymerization catalyst comprising specific catalystcomponents (A), (B), and (C) described below.

Component (A): Bridged cyclopentadienyl indenyl compound containing atransition metal element

Component (B): A compound capable of reacting with the compound of thecomponent (A) to form a cationic metallocene compound

Component (C) Inorganic compound carrier

2-1. Catalyst Component (A)

The catalyst component (A), which is preferred for the production of theethylene-α-olefin copolymer of the present invention, is a bridgedcyclopentadienyl indenyl compound containing a transition metal element,preferably a metallocene compound represented by formula [1] below, morepreferably a metallocene compound represented by formula [2] below.

In formula [1], M represents a transition metal of Zr, or Hf, A¹represents a ligand having a cyclopentadienyl ring (conjugatedfive-membered ring) structure, A² represents a ligand having an indenylring structure, represents a linking group that links A¹ and A² at anyposition, and X and Y each independently represent a hydrogen atom, ahalogen atom, a hydrocarbon group of 1 to 20 carbon atoms, an oxygen ornitrogen atom-containing hydrocarbon group of 1 to 20 carbon atoms, anamino group substituted with a hydrocarbon group of 1 to 20 carbonatoms, or an alkoxy group to 20 carbon atoms.

In formula [2], M represents a transition metal of Ti, Zr, or Hf, Q¹represents a linking group that links the cyclopentadienyl ring and theindenyl ring, X and Y each independently represent a hydrogen atom, ahalogen atom, a hydrocarbon group of 1 to 20 carbon atoms, an oxygen ornitrogen atom-containing hydrocarbon group of 1 to 20 carbon atoms, anamino group substituted with a hydrocarbon group of 1 to 20 carbonatoms, or an alkoxy group of 1 to 20 carbon atoms, and ten occurrencesof R each independently represent a hydrogen atom, a halogen atom, ahydrocarbon group of 1 to 20 carbon atoms, a silicon-containinghydrocarbon group having 1 to 18 carbon atoms and 1 to 6 silicon atoms,a halogen-containing hydrocarbon group of 1 to 20 carbon atoms, anoxygen atom-containing hydrocarbon group of 1 to 20 carbon atoms, or asilyl group substituted with a hydrocarbon group of 1 to 20 carbonatoms.

The metallocene compound of formula (1c) described in JP 2013-227271 Ais particularly preferred as the catalyst component (A) for theproduction of the ethylene-α-olefin copolymer of the present invention.

In formula (1c), M^(1c) represents a transition metal of Ti, Zr, or Hf,X^(1c) and X^(2c) each independently represent a hydrogen atom, ahalogen atom, a hydrocarbon group of 1 to 20 carbon atoms, an oxygen ornitrogen atom-containing hydrocarbon group of 1 to 20 carbon atoms, anamino group substituted with a hydrocarbon group of 1 to 20 carbonatoms, or an alkoxy group of 1 to 20 carbon atoms, Q^(1c) and Q^(2c)each independently represent a carbon atom, a silicon atom, or agermanium atom, R^(1C) each independently represent a hydrogen atom or ahydrocarbon group of 1 to 10 carbon atoms, at least two of fouroccurrences of R^(1c) may be linked with Q^(1c) and Q^(2c) to form aring, m^(c) represents 0 or 1 provided that when m^(c) is 0, Q^(1c) isbonded directly to the and R^(2c)-containing conjugated five-memberedring, R^(2c) and R^(4c) each independently represent a hydrogen atom, ahalogen atom, a hydrocarbon group of 1 to 20 carbon atoms, asilicon-containing hydrocarbon group having 1 to 18 carbon atoms and 1to 6 silicon atoms, a halogen-containing hydrocarbon group of 1 to 20carbon atoms, an oxygen atom-containing hydrocarbon group of 1 to 20carbon atoms, or a silyl group substituted with a hydrocarbon group of 1to 20 carbon atoms, and R^(3c) represents a substituted aryl grouprepresented by formula (1-ac) below.

In formula (1-ac), Y^(1c) represents an atom belonging to Group 14, 15,or 16 of the periodic table, R^(5c), R^(6c), R^(7c), R^(8c), and R^(9c)each independently represent a hydrogen atom, a fluorine atom, achlorine atom, a bromine atom, a hydrocarbon group of 1 to 20 carbonatoms, an oxygen- or nitrogen-containing hydrocarbon group of 1 to 20carbon atoms, an amino group substituted with a hydrocarbon group of 1to 20 carbon atoms, an alkoxy group of 1 to 20 carbon atoms, asilicon-containing hydrocarbon group having 1 to 18 carbon atoms and 1to 6 silicon atoms, a halogen containing hydrocarbon group of 1 to 20carbon atoms, or a silyl group substituted with a hydrocarbon group of 1to 20 carbon atoms, adjacent ones of R^(5c), R^(6c), R^(7c), R^(8c), andR^(9c) may be linked together to form a ring together with an atom oratoms bonded thereto, n^(c) represents 0 or 1, provided that when n^(c)is 0, Y^(1c) does not have the substituent R^(5c), and p^(c) represents0 or 1, provided that when p^(c) is 0, the carbon atom bonded to R^(7c)is bonded directly to the carbon atom bonded to R^(9c), provided thatwhen Y^(1c) is a carbon atom, at least one of R^(5c), R^(6c), R^(7c),R^(8c), and R^(9c) is not a hydrogen atom.

The metallocene compound represented by formula (2c) described in JP2013-227271 A is most preferred as the catalyst component (A) for theproduction of the ethylene-α-olefin copolymer of the present invention.

In the metallocene compound represented by formula (2c) above, M^(1c),X^(1c), X^(2c), Q^(1c), R^(1c), R^(2c), and R^(4c) may be selected fromthe corresponding atoms and groups shown in the metallocene compoundrepresented by formula (1c) above. R^(10c) may be selected from theatoms and groups for R^(5c), R^(6c), R^(7c), R^(8c), and R^(9c) shown inthe metallocene compound represented by formula (1c) above.

Examples of the above metallocene compounds include, but are not limitedto, the compounds represented by formula (4c) and shown in Tables 1c-1to 5 and the compounds represented by formulae (5c) and (6c) and shownin Tables 1c-6 to 9 in JP 2013-227271 A.

Examples of the above compounds are preferably zirconium compounds orhafnium compounds, more preferably zirconium compounds.

Two or more of the above bridged cyclopentadienyl indenyl compounds arealso preferably used as the catalyst component for the production of theethylene-α-olefin copolymer of the present invention.

2-2. Catalyst Component (B)

The catalyst component (B) preferable for the production of theethylene-α-olefin copolymer of the present invention is a compoundcapable of reacting with the compound of the component (IV) to form acationic metallocene compound, more preferably the component (B) shownin paragraphs [0064] to [0083] of JP 2013-227271 A, even more preferablythe organoaluminumoxy compound shown in paragraphs [0065] to [0069] ofthe same publication.

2-3. Catalyst Component (C)

The catalyst component (C) preferable for the production of theethylene-α-olefin copolymer of the present invention is an inorganiccompound carrier, more preferably the inorganic compound described inparagraphs [0084] to [0088] of JP 2013-227271 A. In this case, theinorganic compound is preferably the metal oxide described in paragraph[0085] of the publication.

2-4. Method for Producing Olefin Polymerization Catalyst

The ethylene-α-olefin copolymer of the present invention is preferablyproduced by a method or copolymerizing ethylene and the α-olefin usingthe olefin polymerization catalyst comprising the catalyst components(A) to (C). The method for bringing the catalyst components (A) to (C)into contact with one another to form the olefin polymerization catalystmay be typically, but not limited to, any of the methods (I) to (III)shown below.

(I) A method comprising bringing the transition metalelement-containing, bridged cyclopentadienyl indenyl compound as thecatalyst component (A) into contact with the catalyst component (B)capable of reacting with the compound of the catalyst component (A) toform a cationic metallocene compound and then bringing the inorganiccompound carrier as the catalyst component (C) into contact.

(II) A method comprising bringing the catalyst components (A) and (C)into contact with each other and then bringing the catalyst component(B) into contact.

(III) A method comprising bringing the catalyst components (B) and (c)into contact with each other and then bringing the catalyst component(A) into contact.

Among these contact methods, the methods (I) and are preferred, and themethod (I) is most preferred. In all the contact methods, the respectivecomponents are generally brought into contact with each other in aninert atmosphere such as nitrogen or argon in the presence of an inertliquid hydrocarbon such as an aromatic hydrocarbon (generally of 6 to 12carbon atoms) such as benzene, toluene, xylene, or ethylbenzene or analiphatic or alicyclic hydrocarbon (generally of 5 to 12 carbon atoms)such as pentane, heptane, hexane, decane, dodecane, or cyclohexane,either with or without stirring. The contact is generally performed at atemperature of −100° C. to 200° C., preferably at a temperature of −50°C. to 100° C., more preferably at a temperature of 0° C. to 50° C., for5 minutes to 50 hours, preferably for 30 minutes to 24 hours, morepreferably for 30 minutes to 12 hours.

As mentioned above, the process of bringing the catalyst components (A),(B), and (C) into contact with one another may be performed using any ofan aromatic hydrocarbon solvent, in which some of the components aresoluble or less soluble, and an aliphatic or alicyclic hydrocarbonsolvent, in which some of the components are insoluble or less soluble.

When the contact reactions between the respective components areperformed in a stepwise manner, the solvent used in the earlier stagemay be used directly as the solvent for the later contact reactionwithout being removed. The contact method may also comprise performingan earlier contact reaction using a soluble solvent, then adding aninert liquid hydrocarbon (such as an aliphatic, alicyclic, or aromatichydrocarbon such as pentane, hexane, decane, dodecane, cyclohexane,benzene, toluene, or xylene), in which some of the components areinsoluble or less soluble, to collect the desired product as a solid, ortemporarily removing part or the whole of the soluble solvent by dryingor other means to take out the desired product as a solid, and thensubjecting the desired product to a later contact reaction using any ofthe above inert hydrocarbon solvents. In the present invention, thecontact reaction of each component may also be performed a plurality oftimes.

In the present invention, the catalyst components (A), (B), and (C) arepreferably used in ratios within the range shown below although they maybe used in any ratios.

When an organoaluminumoxy compound is used as the catalyst component(B), the atomic ratio (Al/M) of aluminum in the organoaluminumoxycompound to the transition metal (M) in the catalyst component (A) isgenerally in the range of 1 to 100,000, preferably 100 to 1,000, morepreferably 210 to 800, even more preferably 250 to 500. When a boranecompound or a borate compound is used, the atomic ratio (B/M) of boronto the transition metal (M) in the catalyst component (A) is generallyselected in the range of 0.01 to 100, preferably 0.1 to 50, morepreferably 0.2 to 10. When a mixture of an organoaluminumoxy compoundand a borane or borate compound is used as the catalyst component (B),the content of each compound in the mixture is preferably selected so asto have the same ratio to the transition metal (M) as shown above.

The catalyst component (C) may be used in an amount of 1 g per 0.0001 to5 millimoles, preferably 0.001 to 0.2 millimoles, more preferably 0.005to 0.1 millimoles, even more preferably 0.01 to 0.04 millimoles of thetransition metal in the catalyst component (A).

In the present invention, the ratio of the number of moles of the metalin the catalyst component (B) to 1 g of the catalyst component (C) ispreferably more than 0.006 to 0.020 (moles/g), more preferably more than0.006 to 0.015 (moles/g), even more preferably more than 0.006 to 0.012(moles/g), further more preferably 0.007 to 0.010 (moles/g).

The olefin polymerization catalyst can be obtained as a solid catalystby bringing the catalyst components (A), (B), and (C) into contact withone another using the method appropriately selected from the contactmethods (I) to (III) and then removing the solvent. The removal of thesolvent may be performed under the ambient pressure or reduced pressureat 0 to 200° C., preferably 20 to 150° C., more preferably 20 to 100° C.for 1 minute to 100 hours, preferably 10 minutes to 50 hours, morepreferably 30 minutes to 20 hours.

The olefin polymerization catalyst may also be obtained by the method(IV) or (V) shown below.

(IV) A method comprising bringing the catalyst components (A) and (C)into contact with each other, removing the solvent to form a solidcatalyst component, and bringing the solid catalyst component intocontact with an organoaluminumoxy compound, a borane compound, a boratecompound, or any mixture thereof under polymerization conditions.

(V) A method comprising bringing the catalyst component (C) into contactwith an organoaluminumoxy compound, a borane compound,a borate compound,or any mixture thereof as the catalyst component (B), removing thesolvent to form a solid catalyst component, and bringing the solidcatalyst component into contact with the catalyst component underpolymerization conditions.

Also in the case of the contact method (IIV) or (V), the same conditionsas described above may be used with respect to the component ratio, thecontact conditions, and solvent removal conditions.

A well-known layered silicate such as that described in JP H05-301917 Aor JP H08-127613 A may also be used as a component for serving as boththe catalyst component (B) (capable of reacting with the catalystcomponent (A) to form a cationic metallocene compound) and the catalystcomponent (C) for the olefin polymerization catalyst preferable for theproduction of the ethylene-α-olefin copolymer of the present invention.A layered silicate is a silicate compound having a crystal structure inwhich planes formed by ionic bonding or the like are stacked in parallelwith a weak bonding force. Although most layered silicates naturallyoccur as main components of clay minerals, not only naturally-occurringlayered silicates but also synthetic silicates may be used.

Preferred examples thereof include montmorillonite, sauconite,beidellite, nontronite, saponite, hectorite, stevensite, bentonite,smectite group minerals such as taeniolite, vermiculite group minerals,and mica group minerals.

The catalyst component (A) and the layered silicate carrier arepreferably used in a ratio within the range shown below, although theymay be used in any ratio. The amount of the catalyst component (A)supported per 1 g of the layered silicate carrier may be 0.0001 to 5millimoles, preferably 0.001 to 0.5 millimoles, more preferably 0.01 to0.1 millimoles.

If necessary, the olefin polymerization catalyst obtained as describedabove may be used after the monomers are subjected to prepolymerization.

2-5. Polymerization Method for Ethylene-α-Olefin Copolymer

The ethylene-α-olefin copolymer of the present invention is preferablyproduced by copolymerizing ethylene and the α-olefin using the olefinpolymerization catalyst prepared by the method described above in thesection 2-4.

As mentioned above, an α-olefin of 3 to 10 carbon atoms may be used as acomonomer. Two or more α-olefins may also be copolymerized withethylene. Any comonomer other than the α-olefin may also be used in asmall amount.

In the present invention, the copolymerization reaction is preferablyperformed by a gas phase method or a slurry method. In the case of gasphase polymerization, ethylene and the comonomer or comonomers arepolymerized by introducing, distributing, or circulating gas flows ofethylene and the commoner or comonomers into or in a reaction vesselwhile oxygen, water, and other gases are substantially shut off. In thecase of slurry polymerization, ethylene and the comonomer or comonomersare polymerized in the presence or absence of an inert hydrocarbonsolvent selected from an aliphatic hydrocarbon such as isobutene,hexane, or heptane, an aromatic hydrocarbon such as benzene, toluene, orxylene, and an alicyclic hydrocarbon such as cyclohexane ormethylcyclohexane. It will be understood that a liquid monomer such asliquid ethylene or liquid propylene may also be used as a solvent. Inthe present invention, gas phase polymerization is more preferred. Thepolymerization conditions generally used include a temperature of 0 to250° C., preferably 20 to 110° C., more preferably 60 to 100° C., apressure in the range of ambient pressure to 10 MPa, preferably ambientpressure to 4 MPa, more preferably 0.5 to 2 MPa, and a polymerizationtime of 5 minutes to 20 hours, preferably 30 minutes to 10 hours.

In order to obtain a copolymer with long-chain branching in anappropriate range and with a relatively narrow comonomer compositiondistribution having an appropriate content of low-density,high-molecular-weight components (one of the features of the presentinvention), appropriate preparation can be achieved by selecting thetype of the catalyst components and (B) to be used and changingpolymerization conditions such as the molar ratio between the catalystcomponents (A) and (B), (A) and (C), or (B) and (C), the polymerizationtemperature, the ethylene partial pressure, the H2/C2 ratio, and thecomonomer/ethylene ratio.

Specifically, for example, when the complex shown in Example 1 below isused, the catalyst may be controlled under the following conditions: thecomplex/silica=10 to 40 μmol/g and organoaluminumoxy compound/silica=7to 10 mmol/g, a modifier may be used as needed, and the polymerizationconditions may be appropriately set in the following ranges: 60 to 90°C., ethylene partial pressure 0.3 to 2.0 MPa, H2/C2 (%)=0.2 to 2.0%, andC6/C2=0.1 to 0.8%.

An agent for removing water, specifically, what is called a scavengermay also be added to the polymerization system. Even in such a case, thepolymerization can also be performed without any trouble.

Examples of such a scavenger that may be used include organoaluminumcompounds such as trimethylaluminum, triethylaluminum, andtriisobutylaluminum, the organoaluminumoxy compound, branchedalkyl-containing modified organoaluminum compounds, organozinc compoundssuch as diethylzinc and dibutylzinc, organomagnesium compounds such asdiethylmagnesium, dibutylmagnesium, and ethylbutylmagnesium, andGrignard compounds such as ethylmagnesium chloride and butylmagnesiumchloride. Among them, triethylaluminum, triisobutylaluminum, andethylbutylmagnesium are preferred, and triethylaluminum is particularlypreferred.

The long-chain branching structure (namely g_(c)) and the copolymerizedcomonomer composition distribution (namely X and W₁ to W₄) of thecopolymer formed (one of the features of the present invention) can becontrolled by changing polymerization conditions such as the molar ratioof the catalyst, the polymerization temperature and pressure, and thepolymerization time or changing the polymerization process, although therange of the long-chain branching structure and the compositiondistribution are substantially determined by the type of the catalystcomponents (A) and (B). Even when the catalyst component speciesselected tends to produce a long-chain branching structure, a copolymerwith a low content of a long-chain branching structure can be producedthrough, for example, lowering the polymerization temperature or raisingthe pressure of ethylene. Even when the catalyst component speciesselected tends to widen the molecular weight distribution or thecopolymerized composition distribution, a copolymer with a narrowmolecular weight distribution or a narrow copolymerized compositiondistribution can be produced through, for example, changing the molarratio between the catalyst components, the polymerization conditions, orthe polymerization process.

If the polymerization conditions are appropriately selected, theethylene-α-olefin copolymer of the present invention could be producedeven by a two or multi-stage polymerization process in which the stagesdiffer from one another in polymerization conditions such as thehydrogen concentration, the amount of the monomers, the polymerizationpressure, and the polymerization temperature. However, theethylene-α-olefin copolymer of the present invention should preferablybe produced by single-stage polymerization reaction, so that it can beproduced more economically without setting of complicated polymerizationoperation conditions.

3-1. Olefin Resin Composition

In view of its significant modification effect, the ethylene-α-olefincopolymer of the present invention can be used together with anadditional olefin resin to form an olefin resin composition.

The additional olefin resin may be an ethylene resin such as anotherethylene-α-olefin copolymer (B) different from the ethylene-α-olefincopolymer of the present invention (hereinafter referred to as the“ethylene-α-olefin copolymer (A)”) or any other olefin resin.

For the purpose of modification, the content of the ethylene-α-olefincopolymer (A) in the resin composition is preferably 1 to 59% by weight,more preferably 1 to 49% by weight, even more preferably 3 to 39% byweight, based on 100% by weight of the resin composition.

3-2. Additional Ethylene-α-Olefin Copolymer (B)

The additional ethylene-α-olefin copolymer (B) may be linear low-densitypolyethylene (LLDPE) having substantially no long-chain branchingstructure, having a linear molecular structure, and obtained using, forexample, a Ziegler catalyst, or may be metallocene polyethylene having alinear molecular structure and a narrower molecular weight distributionand obtained using a metallocene catalyst.

In particular, an ethylene-α-olefin copolymer satisfying physicalproperties (B-1) and (B-2) below is preferably used, so that thecopolymer (A) exerts its modification effect.

(B-1) MFR=0.01 to 20 g/10 minutes

(B-2) Density=0.880 to 0.970 g/cm³

Metallocene polyethylene satisfying physical property (B-3) below ismore preferably used as the additional ethylene-α-olefin copolymer (B),so that the copolymer (A) more effectively exerts its modificationeffect.

(B-3) Mw/Mn=2.0 to 4.0

In this regard, MFR, density, Mw/Mn have the same meanings as thosedefined above for the copolymer (A).

1-1. Condition (B-1)

The ethylene-α-olefin copolymer (B) may have a melt flow rate (MFR_(B))of 0.01 to 20.0 g/10 minutes, preferably 0.1 to 5.0 g/10 minutes. When acopolymer with a relatively wide molecular weight distribution (whichoften exhibits a Q value (described later) of more than 3.0) obtainedusing a Ziegler catalyst is used as the copolymer (B), it morepreferably has a MFR in the range of 0.3 to 3.0 g/10 minutes. On theother hand, when a copolymer with a relatively narrow molecular weightdistribution (which often exhibits a Q value (described later) of 2.0 toobtained using a metallocene catalyst is used as the copolymer (B), morepreferably has a MFR in the range of 0.3 to 4.0 g/10 minutes. Thecopolymer (B) with too low a MFR_(B) can have low moldability, whereasthe copolymer (B) with too high a MFR_(B) can have a reduced level ofimpact resistance, mechanical strength, or other properties.

1-2. Condition (B-2)

The ethylene-α-olefin copolymer (B) may have a density_(B) of 0.880 to0.970 g/cm³, preferably0.880 to 0.950 g/cm³, more preferably 0.890 to0.940 g/cm³. The copolymer (B) with a density_(B) in this range has agood balance between impact resistance and stiffness. The copolymer (B)with too low a density_(B) may have reduced stiffness and lacksuitability for automatic bag-making. The copolymer (B) with too high adensity_(B) may lack impact resistance.

Condition (B-3)

The ethylene-α-olefin copolymer (B) may have a ratio [Mw/Mn]_(B)(hereinafter also referred to as a Q value) of weight average molecularweight (Mw) to number average molecular weight (Mn) of 2.0 to 10.0. Theethylene-α-olefin copolymer (B) with a Q value of less than 2.0 mayresist mixing with other polymer components. If the Q value exceeds10.0, the effect of improving impact resistance will be insufficient,and the balance between impact resistance and stiffness will hedisturbed. For the balance between impact resistance and stiffness, theQ value preferably has an upper limit of 7.5 or less, more preferably5.0 or less. The Q value preferably has a lower limit of 2.3 or more,more preferably 2.5 or more.

When a copolymer obtained with a Ziegler catalyst is used as thecopolymer (B), it preferably has a Q value or more than 3.0 but not morethan 5.0 g/10 minutes. When a copolymer obtained with a metallocenecatalyst is used as the copolymer (B), it preferably has a Q value of2.0 to 4.0 g/10 minutes. The ratio [Mw/Mn]_(B) between the weightaverage molecular weight (Mw) and the number average molecular weight(Mn) of the ethylene-α-olefin copolymer (B) refers to the value measuredunder the conditions below (hereinafter also referred to as “the methodfor measuring the molecular weight distribution”). Mw/Mn is defined asthe ratio (Mw/Mn) between the weight average molecular weight (Mw) andthe number average molecular weight (Mn) measured by gel permeationchromatography (GPC).

1-4. Composition of Ethylene-α-Olefin Copolymer (B)

The ethylene-α-olefin copolymer (B) component may be a copolymer ofethylene and an α-olefin of 3 to 20 carbon atoms. In this case, theα-olefin used as a component to be copolymerized may be the same as thatused for the ethylene-α-olefin copolymer described above.

As regards the contents of ethylene and α-olefin units, theethylene-α-olefin copolymer (B) may include about 80 to 100% by weightof the ethylene unit and 0 to about 20% by weight of the α-olefin unit,preferably about 85 to about 99.9% by weight of the ethylene unit andabout 0.1 to about 15% by weight of the α-olefin unit, more preferablyabout 90 to about 99.5% by weight of the ethylene unit and about 0.5 toabout 10% by weight of the α-olefin unit, even more preferably about 90to about 99% by weight of the ethylene unit and about 1 to about 10% byweight of the α-olefin unit. When the ethylene unit content falls withinthis range, the polyethylene resin composition or the molded productthereof has a good balance between stiffness and impact strength.

1-5. Method for Producing Ethylene-α-Olefin Copolymer (B)

The ethylene-α-olefin copolymer (13) can be produced by a method ofhomo-polymerization of ethylene or copolymerization of ethylene and theα-olefin using an olefin polymerization catalyst.

There are now known a variety of olefin polymerization catalysts, andany olefin polymerization catalyst may be used as long as theethylene-α-olefin copolymer (B) can be prepared within the limits ofmodification of the composition of catalyst components, polymerizationconditions, and post treatment conditions. However, examples of olefinpolymerization catalysts suitable for the production of theethylene-α-olefin copolymer (B) include transition metal-containingcatalysts (i) and (ii) described below, which are technical exampleseconomically satisfactory at an industrial level.

(i) Ziegler Catalyst

A Ziegler-Natta catalyst comprising a combination of a transition metalcompound and an alkyl compound of a typical metal or the like andserving as a catalyst for olefin coordination polymerization is anexample of the olefin polymerization catalyst preferable for theproduction of the ethylene-α-olefin copolymer (B). In particular, whatis called a Mg—Ti Ziegler catalyst (see, for example, Shokubai KatsuyouDaijiten (Practical Dictionary of Catalysts) published by KogyoChosakai, 2004 and Shutsugan Keitou Zu—Olefin Jugo Shokubai noHensen—(Application Flow Chart—History of Olefin PolymerizationCatalyst—) published by Japan Institute of Invention and Innovation,comprising a combination of an organoaluminum compound and a solidcatalyst component comprising a titanium compound supported on amagnesium compound is preferred because of its low price, high activity,and high suitability for polymerization process.

(ii) Metallocene Catalyst

A metallocene catalyst comprising a metallocene transition metalcompound and a co-catalyst component and serving as an olefinpolymerization catalyst (see, for example, Metallocene Shokubai ni-yoruJisedai Polymer Kogyoka Gijutsu (Next-Generation Polymer EngineeringTechnology with Metallocene Catalysts) (Vol. 1 & 2) published byInter-Research, 1994) can be used as another example of thepolymerization catalyst preferable for the production of theethylene-α-olefin copolymer (B) because it is relatively inexpensive,has high activity and high suitability for polymerization process, andallows the production of ethylene polymers with a narrow molecularweight distribution and a narrow copolymer composition distribution.

II. Olefin Resin Composition

Hereinafter, a detailed description will be given of an olefin resincomposition comprising, as main components, the ethylene-α-olefincopolymer (A) of the present invention and an additionalethylene-α-olefin copolymer (B) other than the copolymer (A) and beingsuitable mainly for film applications.

Specifically, the olefin resin composition for use in films or sheetsmay be a composition comprising: 1 to 49% by weight, preferably 3 to 35%by weight of the specific ethylene-α-olefin copolymer (A) of the presentinvention; and 99 to 51% by weight, preferably 75 to 97% by weight of anadditional ethylene-α-olefin copolymer (B) other than the copolymer (A).Optionally, the composition more preferably comprises 1 to 30% by weightof an additional olefin resin component (C).

1. MFR

The film-forming olefin resin composition comprising the components (A)and (B) needs to have a MFR of 0.01 to 20 g/10 minutes, and preferablyhas a MFR of 0.05 to 10 g/10 minutes, more preferably 0.10 to 5 g/10minutes.

The composition with a MFR of less than 0.01 g/10 minutes can have poorfluidity and cause too high a load on an extruder motor. On the otherhand, the composition with a MFR of more than 20 g/10 minutes can makebubbles unstable, be difficult to mold, and form a film with lowstrength.

The MFR of the olefin resin composition is the value measured under theconditions of 100° C. and a load of 21.18 N (2.16 kg) according to JIS K7210. Approximately, the MFR can be calculated from the MFRs of thecomponents (A) and (B) and their contents according to the sum rule.

2. Density

The olefin resin composition of the present invention comprising thecomponents (A) and (B) needs to have a density of 0.910 to 0.950 g/cm³,and preferably has a density of 0.910 to 0.945 g/cm³, more preferably0.915 to 0.940 g/cm³.

The olefin resin composition with a density of less than 0.910 g/cm³ canform a low-stiffness film and have reduced suitability for automaticbag-making machines. The olefin resin composition with a density of morethan 0.950 g/cm³ can form a film with reduced strength.

The density of the olefin resin composition can be calculated from thedensities of the components (A) and (B) and their contents according tothe sum rule.

3. Relation Between MFRs of Components (A) and (B)

The components (A) and (B) used to form the olefin resin composition ofthe present invention preferably satisfy the relation MFR_(B)>MFR_(A) orthe relation 20>MFR_(B)/MFR_(A)>1.0, more preferably the relation15.0>MFR_(B)/MFR_(A)>1.0, even more preferably the relation10.0>MFR_(B)/MFR_(A)>1.0, wherein MFR_(A) and MFR_(B) represent the MFRsof the components (A) and (B), respectively.

When the MFRs of the components (A) and (B) satisfy the relationMFR_(B)>MFR_(A), the addition of the component (A) can make bubbles morestable. When the relation 20>MFR_(B)/MFR_(A)>1.0 is satisfied, bubblescan be stabilized during blown film molding in which the component (B)is added, so that the molding properties can be improved.

4. Relation Between [Mw/Mn] of Components (A) and (B)

The components (A) and (B) used to form the olefin resin composition ofthe present invention preferably satisfy the relation[Mw/Mn]_(B)<[Mw/Mn]_(A), wherein [Mw/Mn]_(A) represents the [Mw/Mn] ofthe component (A), and [Mw/Mn]_(B) represents the [Mw/Mn] of thecomponent (B).

When the [Mw/Mn] of the component (A) and the [Mw/Mn] of the component(B) satisfy the relation [Mw/Mn]_(B)<[Mw/Mn]_(A), bubbles can bestabilized during blown film molding in which the component (B) isadded, so that the molding properties can be improved.

6. Other Components

In the present invention, if necessary, a known additive such as anantistatic agent, an antioxidant, anti-blocking agent, a nucleatingagent, a lubricant, an anti-fogging agent, an organic or inorganicpigment, an ultraviolet absorber, or a dispersing agent may be added tothe composition as long as the features of the present invention are notimpaired.

The olefin resin composition of the present invention may be produced inthe form of pellets by mixing the ethylene-α-copolymer (A), theadditional olefin resin, and optionally added or compounded additivesand resin components using a Henschel mixer, Super Mixer, a tumblermixer, or the like and then heating and kneading the mixture using auniaxial or biaxial extruder, a kneader, or the like.

III. Applications of Ethylene-α-Olefin Copolymer (A) or Olefin ResinComposition

The ethylene-α-olefin copolymer (A) of the present invention, which isremarkably effective in improving particularly the balance betweenimpact strength and stiffness, can be used as a resin modifier, which isto be added to other olefin resins. The ethylene-α-olefin copolymer (A)of the present invention can also be used alone to form films and otherproducts. Therefore, the ethylene-α-olefin copolymer (A) of the presentinvention or the olefin resin composition containing the copolymer (A)can be subjected to a known molding method such as blown film molding,T-die film molding, or any other extrusion molding, injection molding,or compression molding to form a variety of molded products.

The molded product of the copolymer (A) or the polyethylene resincomposition according to the present invention can be produced bymolding the copolymer (A) or the polyethylene resin compositiondescribed above in the section [II]. The molding may be performed withreference to any conventionally known molding methods.

The molded product of the present invention may be formed by any methodthat allows effective use of the superior molding properties, mechanicalproperties, and transparency of the polyethylene resin composition ofthe present invention. When the polyethylene resin composition is formedinto a film, bag, or sheet, which is an example of the main intended useof the composition, preferred examples of the molding method, moldingconditions, and use include, but not limited to, various blown filmmolding methods, T-die film molding methods, calender molding methods,multilayer film forming methods using a multilayer co-extrusion machineor a lamination process, and various uses therefrom.

The thickness of the film (or sheet) product obtained in such a way isnot limited, and the preferred thickness thereof varies with the moldingmethod or conditions. For example, a film (or sheet) with a thickness ofabout 5 to about 300 μm may be obtained by blown film molding, and afilm (or sheet) with a thickness of about 5 μm to about. 5 mm may beobtained by T-die molding. The polyethylene resin composition of thepresent invention can also be used as a modifier to improve moldability,mechanical strength, or other properties by being blended in a suitableamount with any other polyethylene resin, polyethylene resincomposition, or polyolefin resin such as polypropylene resin.

EXAMPLES

Hereinafter, the present invention will be more specifically describedwith reference to examples and comparative examples, which willdemonstrate the excellence of the present invention and the superiorityof the features of the present invention, but are not intended to limitthe present invention.

The measurement methods used in the examples and the comparativeexamples are as shown below. The catalyst synthesis process and thepolymerization process described below were all performed under apurified nitrogen atmosphere, and the solvent used had undergonedehydration and purification with molecular sieve 4A.

[Methods for Evaluating Film]

(1) Tensile Modulus:

According to JIS K 7127:1999, the tensile modulus of the film wasmeasured when the film was deformed by 1% in the machine direction (MDdirection) of the film and in the transverse direction (TD direction) ofthe film.

(2) Dart Drop Impact Strength

The dart drop impact strength of the film was measured by the methodaccording to JIS K7124 1A.

[Blown Film Molding Conditions]

The film to be evaluated was formed by blown film molding under themolding conditions below using an blown film forming machine (moldingapparatus) equipped with a 50 mmφ extruder shown below.

Apparatus: Blown film molding apparatus

Extruder screw diameter: 50 mmφ

Die diameter: 75 mmφ

Extrusion rate: 15 kg/hr

Die lip gap: 3.0 mm

Drawing rate: 20.0 m/minute

Blow-up ratio: 2.0

Resin molding temperature: 170 to 190° C. (shown in the examples)

Film thickness: 30 μm

Example 1

(1) Synthesis of Bridged Cyclopentadienyl Indenyl Compound

Dimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride was synthesized as shown belowaccording to the method described in paragraphs [0140] to [0143] of JP2013-227271 A.

(II) Materials Used

[Synthesis of Metallocene Compound]

(i) Metallocene compound A: Synthesis ofdimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride (1-1) Synthesis of4-(4-trimethylsilyl-phenyl)-indene

To a 500-ml flask were added 10.0 g (51.5 mmol) of4-trimethylsilylphenylboronic acid and 200 ml of dimethoxyethane to forma solution. Subsequently, 27.3 g (128 mmol) of potassium phosphate, 100ml of water, 8.37 g (43.0 mmol) of 4-bromoindene, 0.22 g (0.86 mmol) oftriphenylphosphine, and 0.300 g (0.430 mmol) of PdCl₂(PPh₃)₂ weresequentially added to the flask and stirred under reflux for 12 hours.After cooling to room temperature, 100 ml of water was added to theflask. After the organic phase was separated, the aqueous phase wasextracted twice with 100 ml of ethyl acetate. The resulting organicphases were combined and washed with brine. Sodium sulfate was thenadded to dry the organic phase. After the sodium sulfate was filtered,the solvent was removed by distillation under reduced pressure. Theresidue was purified on a silica gel column to give 9.0 g (yield 79%) of4-(4-trimethylsilyl-phenyl)-indene as a yellow liquid.

(1-2) Synthesis of (4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)dimethylsilane

To a 200-ml flask were added 16.2 g (61.2 mmol) of4-(4-trimethylsilyl-phenyl)-indene and 100 ml of THF to form a solution.After the solution was cooled to −78° C., 29.4 ml (173.5 mmol) of ann-butyllithium/hexane solution (2.5M) was added to the solution. Themixture was returned to room temperature and stirred for 4 hours. A300-ml flask was separately provided, to which 14.8 ml (122 mmol) ofdimethyldichlorosilane and 20 ml of THF were added to form a solution.The solution was cooled to −78° C., to which the reaction solutionobtained previously was added. The mixture was returned to roomtemperature and stirred for 12 hours. The volatile matter was removed bydistillation under reduced pressure, so that 21.8 g of a yellow solutionwas obtained. To the yellow solution was added 80 ml of THF to form asolution, to which 36.7 ml (73.5 mmol) of a CpNa/THF solution (2M) wasadded at −30° C. The mixture was returned to room temperature andstirred for 1 hour, and then 100 ml of ice water was added thereto. Thereaction mixture was extracted twice with 100 ml of ethyl acetate. Theresulting organic phases were combined and washed with brine. Sodiumsulfate was then added to dry the organic phase. After the sodiumsulfate was filtered, the solvent was removed by distillation underreduced pressure. The residue was purified on a silica gel column togive 12.0 g (yield 51%) of (4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)dimethylsilane as a yellow liquid.

(1-3) Synthesis of dimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride

To a 300-ml flask were added 1.20 g (3.00 mmol) of(4-(4-trimethylsilylphenyl)indenyl) (cyclopentadienyl)dimethylsilane and20 ml of diethyl ether and then cooled to −70° C. To the mixture wasdropwise added 2.60 ml (6.60 mmol) of a 2.5 mol/Ln-butyllithium-n-hexane solution. After the completion of dropwiseaddition, the mixture was returned to room temperature and stirred for 2hours. The solvent was removed from the reaction liquid by distillationunder reduced pressure. After 30 ml of dichloromethane was added to theresidue, the mixture was cooled to −70° C. in a dry ice-methanol bath.To the mixture was then added 0.770 g (3.30 mmol) of zirconiumtetrachloride. Subsequently, the mixture was stirred overnight whilegradually returned to room temperature. After the reaction liquid wasfiltered, the solvent was removed from the resulting filtrate bydistillation under reduced pressure, so that a yellow powder wasobtained. The powder was recrystallized from 10 ml of toluene to give0.500 g (yield 31%) ofdimethylsilylene(4-(4-trimethylsilylphenyl)indenyl)(cyclopentadienyl)zirconium dichloride as a yellow crystal.

¹H-NMR values (CDCl₃): δ 0.21 (s, 3H), δ 0.23 (s, 9H), δ 0.43 (s, 3H), δ5.48 (m, 1H), δ 5.51 (m, 1H), δ 5.81 (d, 1H), δ 6.60 (m, 1H), δ 6.66 (m,1H), δ 6.95 (dd, 1H), δ 7.13 (s, 1H), δ 7.39 (dd, 2H), δ 7.57 (d, 2H), δ7.95 (d, 2H).

(2) Synthesis of Olefin Polymerization Catalyst

Under a nitrogen atmosphere, 30 g of silica, which had been baked at400° C. for 5 hours, was added to a 500-ml three-neck flask and thendried under reduced pressure for 1 hour using a vacuum pump while heatedat 150° C. in an oil bath. Under a nitrogen atmosphere, 410 mg ofdimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride synthesized in the section (1)was added to a 200-ml two-neck flask provided separately, and dissolvedwith 80.4 ml of dehydrated toluene. At room temperature, 82.8 ml of a20% methylaluminoxane/toluene solution manufactured by AlbemarleCorporation was then added to the resulting solution and stirred for 30minutes. The whole amount of the toluene solution of the reactionproduct of the zirconocene complex with methylaluminoxane was added tothe 500-ml three-neck flask containing vacuum-dried silica, while theflask was heated with stirring in an oil bath at 40° C. After themixture was stirred at 40° C. for 1 hour, the toluene solvent wasremoved by distillation under reduced pressure with heating at 40° C.,so that a powdery catalyst was obtained.

(3) Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed using the powdery catalyst obtained in the section (2).Specifically, the polymerization was performed at a constant temperaturewith a constant gas composition in a continuous gas-phase polymerizationapparatus (inner volume 100 L, fluidized bed diameter 10 cm, fluidizedbed seed polymer (dispersant) 1.8 kg) set at a temperature of 75° C., ahexene/ethylene molar ratio of 0.27%, a hydrogen/ethylene molar ratio of0.53%, a nitrogen concentration of 26 mol %, and a total pressure of 0.8MPa while the powdery catalyst was intermittently supplied at a rate of0.21 g/hour to the polymerization apparatus. In order to keep thecleanliness in the system, a hexane-diluted solution of 0.03 mol/Ltriethylaluminum (TEA) was supplied at 15.7 ml/hr to the gas circulationline. As a result, polyethylene was produced at an average rate of 330g/hr. After at least 5 kg of polyethylene was produced in total, anethylene-1-hexene copolymer was obtained with a MFR, of 0.23 g/10minutes and a density of 0.921 g/cm³. The results are shown in Tables 3and 4.

Example 2

(1) Synthesis of Olefin Polymerization Catalyst

Under a nitrogen atmosphere, 30 g of silica, which had been baked at400° C. for 5 hours, was added to a 500-ml three-neck flask, to which195 ml of dehydrated toluene was then added to form a slurry. Under anitrogen atmosphere, 410 mg ofdimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride synthesized in Example 1 (1) wasadded to a 200-ml two-neck flask provided separately, and dissolved with80.4 ml of dehydrated toluene. At room temperature, 82.8 ml of a 20%methylaluminoxane/toluene solution manufactured by Albemarle Corporationwas then added to the resulting solution and stirred for 30 minutes. Thewhole amount of the toluene solution of the reaction product of thezirconocene complex with methylaluminoxane was added to a 500-mlthree-neck flask containing the toluene slurry of silica, while theflask was heated with stirring in an oil bath at 40° C. After stirred at40° C. for 1 hour, the mixture was gently subjected to precipitationwith heating at 40° C. for 15 minutes. After 224 ml of the resultingsupernatant was removed, the toluene solvent was removed by distillationunder reduced pressure, so that a powdery catalyst was obtained.

(2) Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in the section (1) instead of thepowdery catalyst of Example 1 (2). The results are shown in Tables 3 and4.

Example 3

(1) Synthesis of Olefin Polymerization Catalyst

Under a nitrogen atmosphere, 20 g of silica, which had been baked at400° C. for 5 hours, was added to a 500-ml three-neck flask and thendried under reduced pressure for 1 hour using a vacuum pump while heatedat 150° C. in an oil bath. Under a nitrogen atmosphere, 273 mg ofdimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride synthesized in the section (1)was added to a 200-ml two-neck flask provided separately, and dissolvedwith 53.6 ml of dehydrated toluene. At room temperature, 55.2 ml of a20% methylaluminoxane/toluene solution manufactured by AlbemarleCorporation was then added to the resulting solution and stirred for 30minutes. The whole amount of the toluene solution of the reactionproduct of the zirconocene complex with methylaluminoxane was added tothe 500-ml three-neck flask containing vacuum-dried silica, while theflask was heated with stirring in an oil bath at 40° C. After themixture was stirred at 40° C. for 1 hour, the toluene solvent wasremoved by distillation under reduced pressure with heating at 40° C.,so that a powdery catalyst was obtained.

(2) Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in the section (1) instead of thepowdery catalyst of Example 1 (2). The results are shown in Tables 3 and4.

Example 4

Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in Example 2 (2). The results areshown in Tables 3 and 4.

Example 5

Production of Ethylene-1-hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in Example 2 (2). The results areshown in Tables 3 and 4.

Example 6

(1) Synthesis of Olefin Polymerization Catalyst

Under a nitrogen atmosphere, 30 g of silica, which had been baked at400° C. for 5 hours, was added to a 500-ml three-neck flask, to which195 ml of dehydrated toluene was then added to form a slurry. Under anitrogen atmosphere, 412 mg ofdimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride synthesized in Example 1 (1) wasadded to a. 200-ml two-neck flask provided separately, and dissolvedwith 80.7 ml of dehydrated toluene. At room temperature, 78.9 ml of a20% methylaluminoxane/toluene solution manufactured by AlbemarleCorporation was then added to the resulting solution and stirred for 30minutes. The whole amount of the toluene solution of the reactionproduct of the zirconocene complex with methylaluminoxane was added to a500-ml three-neck flask containing the toluene slurry of silica, whilethe flask was heated with stirring in an oil bath at 90° C. Afterstirred at 40° C. for 1 hour, the mixture was gently subjected toprecipitation with heating at 40° C. for 15 minutes. After 221 ml of theresulting supernatant was removed, the toluene solvent was removed bydistillation under reduced pressure, so that a powdery catalyst wasobtained.

(2) Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in the section (1) instead of thepowdery catalyst of Example 1 (2). The results are shown in Tables 3 and4.

Example 7

(1) Treatment of Olefin Polymerization Catalyst

Under a nitrogen atmosphere, 32 g part of the powdery catalyst obtainedExample 6 (1) was added to a 500-ml three-neck flask, to which a liquidmixture of 195 ml of dehydrated hexane and 13.5 g of dehydrated liquidparaffin (MORESCO WHITE P-120 (trade name) manufactured by MORESCOCorporation.) Was added at room temperature. After the liquid mixturewas stirred for 10 minutes, the solvent was removed by distillationunder reduced pressure at 40° C., so that a powdery catalyst wasobtained again.

(2) Production of Ethylene-1-hexene copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in the section (1) instead of thepowdery catalyst of Example 1 (2). The results are shown in Tables 3 and4.

Example 8

(1) Treatment of Olefin Polymerization Catalyst

Under a nitrogen atmosphere, 31 g part of the powdery catalyst obtainedExample 6 (1) was added to a 500-ml three-neck flask, to which a liquidmixture of 195 ml of dehydrated hexane and 12.7 g of dehydrated liquidpolybutene (Nisseki Polybutene LV-7 (trade name) manufactured by JXNippon Oil & Energy Corporation) was added at room temperature. Afterthe mixture was stirred for 10 minutes, the solvent was removed bydistillation under reduced pressure at 40° C., so that a powderycatalyst was obtained again.

(2) Production of Ethylene-1-hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in the section (1) instead of thepowdery catalyst of Example 1 (2). The results are shown in Tables 3 and4.

Example 9

(1) Synthesis of Olefin Polymerization Catalyst

Under a nitrogen atmosphere, 30 g of silica, which had been baked at600° C. for 5 hours, was added to a 500-ml three-neck flask and thendried under reduced pressure for 1 hour using a vacuum pump while heatedat 150° C. in an oil bath. Under a nitrogen atmosphere, 412 mg ofdimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride synthesized in the section (1)was added to a 200-ml two-neck flask provided separately, and dissolvedwith 80.7 ml of dehydrated toluene. At room temperature, 83.1 ml of a20% methylaluminoxane/toluene solution manufactured by AlbemarleCorporation was then added to the resulting solution and stirred for 30minutes. The whole amount of the toluene solution of the reactionproduct of the zirconocene complex with methylaluminoxane was added to a500-ml three-neck flask containing vacuum-dried silica, while the flaskwas heated with stirring in an oil bath at 90° C. After the mixture wasstirred at 40° C. for 1 hour, the toluene solvent was removed bydistillation under reduced pressure with heating at 40° C., so that apowdery catalyst was obtained.

(2) Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in the section (1) instead of thepowdery catalyst of Example 1 (2). The results are shown in Tables 3 and4.

Example 10 (1) Synthesis of Olefin Polymerization Catalyst

A powdery catalyst for olefin polymerization was obtained in the samemanner as in Example 1 (2), except that 421 mg ofdimethylsilylene(3-methyl-4-(4-trimethylsilyl-phenyl)-3-methyl-indenyl)(cyclopentadienyl)zirconium dichloride was used instead ofdimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride.

(2) Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in the section (1) instead of thepowdery catalyst of Example 1 (2). The results are shown in Tables 3 and4.

Example 11 Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using, instead of the powdery catalyst of Example 7 (2), a slurrycatalyst obtained through changing the amount of the dehydrated liquidparaffin to 180 g in the process of Example 7 (1). The results are shownin Tables 3 and 4.

Example 12 Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 11, except that thecopolymerization was performed under the conditions shown in Table 2.The results are shown in Tables 3 and 4.

Example 13 Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 12, except that thecopolymerization was performed under the conditions shown in Table 2,the ethylene partial pressure was changed to 1.5 MPa namely about 3.1times), and the TEA feed rate was changed to 0.05 mmol/hr. The resultsare shown in Tables 3 and 4.

Comparative Example 1 Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in the method for producing the ethylenepolymer (B-8) described in Example 8a (1) of JP 2012-214781 A. Theresults are shown in Tables 3 and 4.

Comparative Example 2

(1) Synthesis of Olefin Polymerization Catalyst

Under a nitrogen atmosphere, 30 g of silica, which had been baked at400° C. for 5 hours, was added to a 500-ml three-neck flask, to which195 ml of dehydrated toluene was then added to form a slurry. Under anitrogen atmosphere, 820 mg ofdimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride synthesized in Example 1 (1) wasadded to a 200-ml two-neck flask provided separately, and dissolved with161 ml of dehydrated toluene. At room temperature, 49.7 ml of a 20%aluminoxane/toluene solution manufactured by Albemarle Corporation wasthen added to the resulting solution and stirred for 30 minutes. Thewhole amount or the toluene solution of the reaction product of thezirconocene complex with methylaluminoxane was added to a 500-mlthree-neck flask containing the toluene slurry of silica, while theflask was heated with stirring in an oil bath at 40° C. After stirred at40° C. for 1 hour, the mixture was gently subjected to precipitationheating at 40° C. for 15 minutes. After 224 ml of the resultingsupernatant was removed, the toluene solvent was removed by distillationunder reduced pressure, so that a powdery catalyst was obtained.

(2) Production of Ethylene-1-Hexene Copolymer

Continuous gas phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in the section (1) instead of thepowdery catalyst of Example 1 (2). The results are shown in Tables 3 and4.

Comparative Example 3

Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in the method for producing the ethylenepolymer (B-5) described in Example 5a (1) of JP 2012-214781 A. Theresults are shown in Tables 2 and 3.

Comparative Example 9

(1) Synthesis of Olefin Polymerization Catalyst

A powdery catalyst for olefin polymerization was obtained in the samemanner as in Comparative Example 2 (1), except that 338 mg ofdimethylsilylenebisindenylzirconium dichloride was used instead of 820mg of dimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconium dichloride.

(2) Production of Ethylene-1-Hexene Copolymer

Continuous gas-phase copolymerization of ethylene with 1-hexene wasperformed in the same manner as in Example 1 (3), except that thecopolymerization was performed under the conditions shown in Table 2using the powdery catalyst obtained in the section (1) instead of thepowdery catalyst of Example 1 (2). The results are shown in Tables 3 and4.

Comparative Example 5

A commercially available ethylene polymer with long-chain branching(CU5001 manufactured by Sumitomo Chemical Co., Ltd., MFR=0.3 g/10minutes, density 0.922 g/cm³) was subjected to analysis. The results ofthe analysis are shown in Tables 3 and 4.

Reference Example 11

Commercially available high-pressure radical process low-densitypolyethylene (LF240 manufactured by Japan Polyethylene Corporation,MFR=0.7 g/10 minutes, density 0.924 g/cm³) was subjected to analysis.The results of the analysis are shown in Tables 3 and 4.

Comparative Example 6

Production of Linear Low-Density Polyethylene (Ethylene-1-HexeneCopolymer) With no Long-Chain Branching

As an example of production of common linear low-density polyethylenewith no long-chain branching, continuous gas-phase copolymerization ofethylene with 1-hexene was performed in the same manner as in the methodfor producing the ethylene polymer (A-1) described in Example 1a (1) ofJP 2012-214781 A, except that the polymerization was performed under theconditions shown in Table 1 using metallocene 4, shown in Table 2, asthe metallocene compound. The results are shown in Tables 3 and 4.

[Film Forming Experiment]

A film forming experiment was performed as described below todemonstrate now the ethylene-α-olefin copolymer of the present inventionis effective in modifying polyolefin resins.

How the ethylene-α-olefin copolymer of the present invention has highperformance as a modifier for polyolefin resin can be demonstrated bymeasuring the physical properties of films that are obtained by blendinga certain amount of a copolymer according to the present invention and acertain amount of a copolymer not according to the present invention,respectively, with a commercially available ethylene polymer and thensubjecting the resulting polyolefin resin compositions, respectively, toblown film molding.

Specifically, the copolymers of Examples 1 to 13, comparative Examples 1to 6, and Reference Example 1 were blended, respectively, with acommercially available ethylene polymer (UF230 manufactured by JapanPolyethylene Corporation, MFR=1.1 g/10 minutes, density 0.921 g/cm³, anethylene-1-butene copolymer) produced with a magnesium titanium Zieglercatalyst, and then the resulting compositions were formed into films byblown film molding. Table 4 shows the blend ratio between thecommercially available ethylene polymer and the copolymer according toor not according to the present invention, the tensile modulus (in unitsof MPa) and dart drop impact strength (DDI in units of g) of theresulting films.

TABLE 2 Polymerization conditions Olefin polymerization catalyst Poly-Average Com- Com- MAO/ MAO/ merization residence Production ActivityComponent ponent ponent Zr/Silica Silica Zr temperature H2/C2 C6/C2 timerate g/g/ Examples (A) (B) (C) μmol/g mmol/g mol/mol ° C. % % hr g/hrhr/MPa Example 1 Metallocene 1 MAO Silica 25 8.0 320 75 0.53 0.27 5.5330 497 Example 2 Metallocene 1 MAO Silica 25 8.0 320 75 0.67 0.28 6.5275 481 Example 3 Metallocene 1 MAO Silica 25 8.0 321 75 0.53 0.25 5.0363 395 Example 4 Metallocene 1 MAO Silica 25 8.0 320 75 0.72 0.24 4.9370 727 Example 5 Metallocene 1 MAO Silica 25 8.0 320 75 0.64 0.30 6.8265 264 Example 6 Metallocene 1 MAO Silica 25 7.6 303 75 0.69 0.26 4.2425 512 Example 7 Metallocene 1 MAO Silica 25 7.6 303 75 0.72 0.25 5.5330 279 Example 8 Metallocene 1 MAO Silica 25 7.6 303 75 0.71 0.24 6.2289 294 Example 9 Metallocene 1 MAO Silica 25 8.0 320 75 0.49 0.40 5.2345 369 Example 10 Metallocene5 MAO Silica 25 8.0 320 75 0.41 1.52 5.8311 482 Example 11 Metallocene 1 MAO Silica 25 8.0 320 75 0.46 0.44 10.3175 72 Example 12 Metallocene 1 MAO Silica 25 8.0 320 80 0.46 0.39 5.9305 304 Example 13 Metallocene 1 MAO Silica 25 8.0 320 85 0.40 0.39 9.3195 241 Comparative 1 Metallocene 1 MAO Silica 25 5.0 200 75 0.55 0.406.3 288 135 Comparative 2 Metallocene 1 MAO Silica 50 4.8 96 75 0.290.46 5.3 338 195 Comparative 3 Metallocene 2 MAO Silica 30 4.1 136 800.05 1.98 6.9 260 320 Comparative 4 Metallocene 3 MAO Silica 25 5.0 20075 0.38 0.54 5.0 360 414 Comparative 5 Commercially available ethylenecopolymer with long-chain branching Reference 1 Commercially availablehigh-pressure radical process low-density polyethylene with long-chainbranching Comparative 6 Metallocene 4 MAO Silica 41 4.0 99 80 0.01 1.826.9 262 312 Metallocene 1:Dimethylsilylene(4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconiumdichloride Metallocene 2: A mixture of trisindenylzirconium hydride andtrisbenzoindenylzirconium hydride Metallocene 3:Dimethylsilylenebisindenylzirconium dichloride Metallocene 4: A productof contact reaction of tetraethoxyzirconium, indene,methylbutylcyclopentadiene, and tripropylaluminum Metallocene 5:Dimethylsilylene(3-methyl-4-(4-trimethylsilyl-phenyl)-indenyl)(cyclopentadienyl)zirconiumdicholoride

TABLE 3 Results of analysis of ethylene-α-olefin copolymer MFR DensityGPC GPC-VIS TREF Condition (1) (g/ Condition (2) Mw/ Condition (3) Mz/Condition (5) Condition (6) Examples (g/10 min) satisfied or not cm3)satisfied or not Mn satisfied or not Mw g_(c)′ satisfied or not X (%)satisfied or not Example 1 0.23 ◯ 0.921 ◯ 3.4 ◯ 2.4 0.71 ◯ 9 ◯ Example 20.13 ◯ 0.919 ◯ 3.9 ◯ 2.6 0.72 ◯ 8 ◯ Example 3 0.34 ◯ 0.919 ◯ 4.1 ◯ 2.60.51 ◯ 7 ◯ Example 4 0.21 ◯ 0.920 ◯ 3.9 ◯ 2.5 0.74 ◯ 12 ◯ Example 5 0.30◯ 0.921 ◯ 4.3 ◯ 2.6 0.67 ◯ 14 ◯ Example 6 0.35 ◯ 0.918 ◯ 4.9 ◯ 3.1 0.64◯ 12 ◯ Example 7 0.22 ◯ 0.922 ◯ 4.8 ◯ 3.2 0.66 ◯ 13 ◯ Example 8 0.25 ◯0.922 ◯ 4.7 ◯ 2.8 0.68 ◯ 13 ◯ Example 9 0.24 ◯ 0.917 ◯ 4.5 ◯ 2.6 0.66 ◯9 ◯ Example 10 0.15 ◯ 0.918 ◯ 4.9 ◯ 2.9 0.50 ◯ 7 ◯ Example 11 0.33 ◯0.916 ◯ 4.5 ◯ 2.7 0.60 ◯ 15 ◯ Example 12 0.26 ◯ 0.918 ◯ 6.9 ◯ 2.6 0.49 ◯13 ◯ Example 13 0.38 ◯ 0.920 ◯ 6.3 X 3.8 0.45 ◯ 15 ◯ Comparative 1 0.21◯ 0.920 ◯ 5.1 ◯ 2.8 0.63 ◯ 13 ◯ Comparative 2 0.25 ◯ 0.921 ◯ 4.7 ◯ 3.50.55 ◯ 24 X Comparative 3 0.30 ◯ 0.922 ◯ 3.9 ◯ 5.0 0.60 ◯ 36 XComparative 4 0.24 ◯ 0.915 ◯ 5.1 ◯ 2.5 0.57 ◯ 7 ◯ Comparative 5 0.30 ◯0.922 ◯ 7.2 X 3.6 0.48 ◯ 9 ◯ Reference 1 0.70 ◯ 0.924 ◯ 5.5 ◯ 3.1 0.26 X1 X Comparative 6 0.90 ◯ 0.920 ◯ 2.9 ◯ 1.9 0.91 X 35 X Results ofanalysis of ethylene-α-olefin copolymer CFC (%) 50% elution logtemperature W1 W2 W3 W2 + Condition (7) Condition (8) Condition (9)Examples Mw (° C.) (%) (%) (%) W4 (%) W3 satisfied or not W2 + W4satisfied or not W2 − W4 satisfied or not Example 1 4.8 76 37 23 23 1746 ◯ 41 ◯ 6 ◯ Example 2 4.9 74 35 24 28 13 52 ◯ 37 ◯ 11 ◯ Example 3 4.870 34 21 27 18 48 ◯ 39 ◯ 4 ◯ Example 4 4.9 76 37 23 29 12 52 ◯ 35 ◯ 11 ◯Example 5 4.9 72 32 20 35 13 55 ◯ 33 ◯ 8 ◯ Example 6 4.9 72 38 22 31 1053 ◯ 31 ◯ 12 ◯ Example 7 4.8 74 34 14 28 13 53 ◯ 38 ◯ 11 ◯ Example 8 4.976 38 21 31 10 52 ◯ 31 ◯ 11 ◯ Example 9 4.9 70 35 18 31 16 49 ◯ 34 ◯ 3 ◯Example 10 4.9 71 37 20 29 15 48 ◯ 34 ◯ 5 ◯ Example 11 4.8 68 35 21 3015 50 ◯ 35 ◯ 6 ◯ Example 12 4.8 70 35 18 32 15 50 ◯ 34 ◯ 3 ◯ Example 135.0 72 39 14 32 15 47 ◯ 29 ◯ 0 ◯ Comparative 1 4.9 68 33 21 34 12 56 X33 ◯ 10 ◯ Comparative 2 4.9 72 33 23 34 10 57 X 33 ◯ 12 ◯ Comparative 35.0 76 35 15 40 10 56 X 25 X 5 ◯ Comparative 4 4.9 66 33 18 31 18 49 ◯36 ◯ 0 X Comparative 5 4.9 72 44 15 25 15 41 ◯ 31 ◯ 0 X Reference 1 4.974 45 14 22 19 36 X 33 ◯ −4 X Comparative 6 5.0 78 33 22 30 16 51 ◯ 37 ◯6 ◯

TABLE 4 Film forming experiment Run 1 Run 2 Run 3 Run 4 Run 5 Run 6 Run7 Run 8 Run 9 Run 10 Run 11 Modifier Polymer type Ex. 1 Ex. 2 Ex. 3 Ex.4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Blend ratio Wt % 20 10 10 20 10 20 20 3010 5 10 Material to be Polyolefin resin PE-3: UF230, MFR 1.1 g/10minutes, density 0.921 g/cm3 modified Blend ratio Wt % 80 90 90 80 90 8080 70 90 95 90 Blown film Elastic modulus MPa 248 241 250 260 248 250253 241 240 255 245 (MD direction) DDI impact g 154 139 133 145 135 151149 163 147 129 145 strength Film forming experiment Run 12 Run 13 Run14 Run 15 Run 16 Run 17 Run 18 Run 19 Run 20 Run 21 Run 22 ModifierPolymer type Comparative 1 Com- Com- Com- Comparative 5 Reference 1parative parative parative 2 3 4 Blend Ratio Wt % 20 10 20 20 20 5 10 200 10 15 Material to be Polyolefin resin PE-3: UF230, MFR 1.1 g/10minutes, density 0.921 g/cm3 modified Blend ratio Wt % 80 90 80 80 80 9590 80 100 90 85 Blown film Elastic modulus MPa 245 245 254 250 237 255250 272 240 270 314 (MD direction) DDI impact g 144 129 132 138 142 119125 115 113 104 96 strength Film forming experiment Run 23 Run 24 Run 25Run 26 Modifier Polymer type Ex. 11 Ex. 12 Ex. 13 Comparative 6 Blendratio Wt % 20 20 20 20 Material to be Polyolefin resin PE-3: UF230, MFR1.1 g/10 minutes, modified density 0.921 g/cm3 Blend ratio Wt % 80 80 8080 Blown film Elastic modulus MPa 300 305 320 420 (MD direction) DDIimpact g 150 145 140 90 strength

(Discussion on the Results in Tables 2 to 4)

In Table 4, Runs 1, 4, 6, 7, 12, 14, and 23 to 25 allows a comparisonbetween the physical properties of films each produced with a blend ofan ethylene polymer PE-3 with 20% of the copolymer (as a modifier) ofone of Examples 1 to 13 according to the present invention (among theethylene-α-olefin copolymers in Table 3 produced using the catalysts andthe polymerization conditions shown in Table 2) and the physicalproperties of films each produced with a blend of PE-3 with thecopolymer of one of Comparative Examples 1 and 2, in which W₂+W₃ did notsatisfy condition (7) because the ratio between the catalyst components(A), (B), and (C) used in these comparative examples differed from thatin these examples although the same catalyst components were used inthese examples and comparative examples. FIG. 6 shows a graph obtainedby plotting the elastic modulus and the impact strength obtained in eachrun with a copolymer blend ratio of 5, 10, or 20%.

The balance between the tensile modulus and impact strength of the filmis significantly better in Runs 1, 4, 6, 7, and 23 to 25 than in Runs 12and. 14, which will show the superiority of the modifier according tothe present invention. The balance between the tensile modulus andimpact strength of films produced using a blend with a smaller amount(10%) of the copolymer of the example according to the present inventionis also better than that in Run 13 using the same amount of thecopolymer of Comparative Example 1. Despite the smaller blended amount(10%), these films have substantially the same level of performance asthat of Run 12 or 14 using a larger amount (20%) of the copolymer ofComparative Example 1 or 2. This also shows the superiority of thecopolymer of the present invention.

In each of Comparative Examples 3, 4, and 6, a copolymer not accordingto the present invention was prepared using another catalyst component(A), and in Comparative Example 5, a commercially availableethylene-α-olefin copolymer was provided, which has long-chain branchingbut is not according to the present invention. Each of these copolymerswas blended as a modifier in an amount of 10% or 20% with the ethylenepolymer PE-3, and the resulting blends were used to form films (Runs 15to 19 and 26). The copolymers of these comparative examples onlyproduced at most the same level of modification effect as the copolymerof Comparative Example 1. The copolymers of these comparative examplesslightly improved the balance between the tensile modulus and the impactstrength of the ethylene polymer PE-3 before the modification, butproduced almost no increase in the impact strength even when ended in alarger amount, in contract to the polymers of the examples according tothe present invention. This will show that all other copolymers areinferior to the copolymer of the present invention.

Next, the usefulness of the copolymer of the present invention as amodifier will be shown by a comparison between the physical propertiesof a film produced using a blend of the ethylene polymer PE-3 with thecopolymer of the present invention and the physical properties of a filmproduced using a blend of PE-3 with high-pressure radical processpolyethylene as a modifier, which is well known as a practical measurefor improving the blown film molding properties of PE-3.

Specifically, in Runs 20 to 22, films were formed using blends of theethylene polymer PE-3 with 0%, 10%, and 15% of commercially availablehigh-pressure process polyethylene. The film molding properties of theblend with 15% of high-pressure process polyethylene in Run 25 wassubstantially the same level (substantially the same level of melttension) as that of the blends with 20 to 30% of the copolymer of thepresent invention in Runs 1, 4, and 6 to 8. However, as regards thetensile modulus and impact strength of the film, the impact strength ofthe film in Run 25 was lower than that of the film of the ethylenepolymer PE-3 alone in Run 23 although the tensile modulus of the film inRun 25 was higher than that of the film of the ethylene polymer PE-3alone in Run 23. In Run 25, the impact strength was not significantlyimproved in contrast to the case using the copolymer of the presentinvention. Therefore, the copolymer of the present invention makes itpossible to provide an excellent technique for producing ethylene-basedfilms that are not available with conventional modification techniques.

Example 10 shows that even when another bridged cyclopentadienyl indenylcompound different from that in Example 1 is used as the catalystcomponent (A), the ethylene-1-hexene copolymer according to the presentinvention can be produced using an increased amount of the catalystcomponent (B) relative to the amount of the catalyst component (C).

The above shows the rational and significance of the elements of thepresent invention and the superiority of the present invention to theconventional art.

INDUSTRIAL APPLICABILITY

As is apparent from the above, the ethylene-α-olefin copolymer of thepresent invention is highly effective, as a modifier for polyolefinresin, in improving molding properties, improving the balance betweenimpact strength and stiffness, and improving transparency. Therefore,the ethylene-α-olefin copolymer of the present invention makes itpossible to provide thinner molded products in an economicallyadvantageous manner.

Therefore, the ethylene-α-olefin copolymer of the present invention,which makes it possible to provide molded products with such favorableproperties in an economically advantageous manner, is of extremely highindustrial value.

1. An ethylene-α-olefin copolymer satisfying the following conditions(1), (2), (5), (7), and (9): (1) the copolymer has a MFR of more than0.1 g/10 minutes but not more than 10 g/10 minutes; (2) the copolymerhas a density of 0.895 to 0.940 g/cm³; (5) the copolymer has a minimumbranching index (gc) of 0.40 to 0.85 as measured for branching index g′in the molecular weight range of 100,000 to 1,000,000 with a GPCmeasurement system comprising a combination of a differentialrefractometer, a viscosity detector, and a light scattering detector;(7) the copolymer has a sum (W₂+W₃) of a content (W₂) and a content (W₃)of more than 40% by weight but less than 56% by weight, wherein W₂ is acontent of components with molecular weights equal to or more than aweight average molecular weight in components eluted at temperaturesequal to or lower than a temperature where an eluted amount determinedfrom an integral elution curve measured by cross fractionationchromatography (CFC) is 50 wt %, and W₃ is a content of components withmolecular weights less than the weight average molecular weight incomponents eluted at temperatures higher than the temperature where theeluted amount determined from the integral elution curve is 50 wt %; and(9) the copolymer has a difference (W₂−W₄) between W₂ and W₄ of morethan 0% by weight but less than 20% by weight, wherein W₄ is an contentof components with molecular weights equal to or more than the weightaverage molecular weight in components eluted at temperatures higherthan the temperature where the eluted amount determined from theintegral elution curve measured by CFC is 50 wt %.
 2. Theethylene-α-olefin copolymer according to claim 1, further satisfying thefollowing condition (1′): (1′) the copolymer has a MFR of more than 0.1g/10 minutes but not more than 1.0 g/10 minutes.
 3. Theethylene-α-olefin copolymer according to claim 1, further satisfying thefollowing condition (2′): (2′) the copolymer has a density of not lessthan 0.898 g/cm³ but less than 0.934 g/cm³.
 4. The ethylene-α-olefincopolymer according to claim 1, wherein the α-olefin has three to tencarbon atoms.
 5. The ethylene-α-olefin copolymer according to claim 1,further satisfying the following condition (3): (3) the copolymer has amolecular weight distribution Mw/Mn of 3.0 to 5.5 as measured by gelpermeation chromatography (GPC).
 6. The ethylene-α-olefin copolymeraccording to claim 1, further satisfying the following condition (4):(4) the copolymer has a molecular weight distribution Mz/Mw of 2.0 to6.0 as measured by GPC.
 7. The ethylene-α-olefin copolymer according toclaim 1, further satisfying the following condition (6): (6) a content(X) of components eluted at 85° C. or higher by temperature risingelution fractionation (TREF) is 2 to 15% by weight.
 8. Theethylene-α-olefin copolymer according to claim 1, further satisfying thefollowing condition (8): (8) the copolymer has a sum (W₂+W₄) of W₂ andW₄ of more than 25% by weight but less than 50% by weight.
 9. A methodfor producing the ethylene-α-olefin copolymer according to claim 1, themethod comprising producing the ethylene-α-olefin copolymer using anolefin polymerization catalyst comprising the following components (A),(B) and (C): (A) a bridged cyclopentadienyl indenyl compound containinga transition metal element; (B) a compound capable of reacting with thecompound of the component (A) to form a cationic metallocene compound;and (C) an inorganic compound carrier.
 10. The ethylene-α-olefincopolymer according to claim 9, wherein a ratio of number of moles of ametal in the component (B) to 1 g of the component (C) is more than0.006 (moles/g) to 0.020 (moles/g).
 11. A method for producing theethylene-α-olefin copolymer according to claim 1, the method comprisingcopolymerizing ethylene and an α-olefin by a gas phase method or aslurry method.
 12. An olefin resin composition comprising: theethylene-α-olefin copolymer (A) according to claim 1; and one or moreother olefin resins.
 13. The olefin resin composition according to claim12, wherein an amount of the ethylene-α-olefin copolymer (A) containedin the resin composition is 1 to 59% by weight.
 14. The olefin resincomposition according to claim 12, which comprises an additionalethylene-α-olefin copolymer (B) other than the copolymer (A) as anolefin resin other than the copolymer (A)
 15. The olefin resincomposition according to claim 14, wherein the ethylene-α-olefincopolymer (B) satisfies the following conditions (B-1) and (B-2): (B-1)the copolymer (B) has a MFR of 0.01 to 20 g/10 minutes; and (B-2) thecopolymer (B) has a density of 0.880 to 0.970 g/cm³.
 16. The olefinresin composition according to claim 15, wherein the ethylene-α-olefincopolymer (B) further satisfies the following condition (B-3): (B-3) thecopolymer (B) has a molecular weight distribution Mw/Mn of 2.0 to 4.0 asmeasured by gel permeation chromatography (GPC).
 17. The olefin resincomposition according to claim 12, wherein the ethylene-α-olefincopolymer (A) and the ethylene-α-olefin copolymer (B) satisfy at leastone of the following conditions: (AB-1) MFR_(B)>MFR_(A); and (AB-2)[Mw/Mn]_(B)<[Mw/Mn]_(A), wherein MFR_(A) represents MFR of theethylene-α-olefin copolymer (A), [Mw/Mn]_(A) represents the molecularweight distribution Mw/Mn of the ethylene-α-olefin copolymer (A)measured by gel permeation chromatography (GPC), MFR_(B) represents MFRof the ethylene-α-olefin copolymer (B), and [Mw/Mn]_(B) represents themolecular weight distribution Mw/Mn of the ethylene-α-olefin copolymer(B) measured by gel permeation chromatography (GPC).
 18. The olefinresin composition according to claim 12, wherein the ethylene-α-olefincopolymer (B) is a linear low-density polyethylene having a MFR of notless than 0.1 but less than 5.0 and produced with a Ziegler catalyst ormetallocene polyethylene having a MFR of not less than 0.1 to but notmore than 10 and produced with a metallocene catalyst.
 19. A filmobtained from the ethylene-α-copolymer according to claim 1.